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Other comprehensive (loss) income, net of tax:

$ (7,542)

$ 15,535

$ (101,941)

^[1]

Foreign currency translation (net of tax effect of $0 for all periods)

1,895

(5,449)

2,351

(133)

(769)

(159)

Total other comprehensive (loss) income

1,762

(6,218)

2,192

Comprehensive (loss) income

$ (5,780)

$ 9,317

$ (99,749)

[1]	The year ended December 31, 2017 has been reported under ASC 605 and has not been adjusted under the modified retrospective approach of ASC 606. See Note 3 – Revenue from contracts with customers for the effect of the adoption of ASC 606 on the Company’s consolidated financial statements.

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

Property Plant And Equipment [Abstract]

Summary of Significant Accounting Policies - Reconciliation of Cash, Cash Equivalents and Restricted Cash (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accounting Policies [Abstract]
Cash and cash equivalents	$ 223,117	$ 35,345
Restricted cash included in other long-term assets	380	340
Total cash, cash equivalents, and restricted cash	$ 223,497	$ 35,685	$ 39,578	$ 17,139

Debt - Schedule of Net Carrying Value of Liability Component of Convertible Notes (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Principal	$ 231,174	$ 31,838
Less: unamortized debt discount	46,820
Less: unamortized debt issuance costs	5,686	$ 90
Convertible Senior Notes Due in 2024 [Member]
Debt Instrument [Line Items]
Principal	230,000
Less: unamortized debt discount	46,820
Less: unamortized debt issuance costs	5,686
Net carrying amount	$ 177,494

Consolidated statement of changes in stockholders' equity (deficit) (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Statement Of Stockholders Equity [Abstract]
Initial public offering issuance costs		$ 4,830
Follow-on public offering, offering costs	$ 370

Goodwill and Other Intangible Assets - Changes in Carrying Amount of Goodwill Attributable to Software Reportable Segment (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
Beginning Balance	$ 210,532	$ 62,706
Acquisitions	21,922	152,630
Effects of foreign currency translation and other	1,229	(4,804)
Ending Balance	$ 233,683	$ 210,532

Leases - Schedule of Supplemental Balance Sheet Information Related to Lease Liabilities (Detail) $ in Thousands	Dec. 31, 2019 USD ($)
Operating leases:
Operating lease ROU assets	$ 28,134
Current portion of operating lease liabilities	9,141
Operating lease liabilities, net of current portion	20,174
Total operating lease liabilities	$ 29,315
Weighted average remaining lease term	4 years 2 months 12 days
Weighted average discount rate	5.60%
Finance leases:
Property and equipment	$ 2,745
Accumulated depreciation	(1,447)
Property and equipment, net	$ 1,298
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:PropertyPlantAndEquipmentMember
Current portion of long-term debt	$ 430
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:LongTermDebtAndCapitalLeaseObligationsCurrent
Long-term debt, net of current portion	$ 744
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	us-gaap:LongTermDebtAndCapitalLeaseObligations
Total finance lease liabilities	$ 1,174
Weighted average remaining lease term	2 years 8 months 12 days
Weighted average discount rate	3.50%

Description of Business - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands				12 Months Ended
	Jun. 07, 2018	Nov. 01, 2017	Oct. 05, 2017	Dec. 31, 2017
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Aggregate proceeds from IPO				$ 119,268
Class B Common Stock [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Conversion from Class B to Class A			2,495,752
IPO [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of shares issued and sold		9,865,004
Price per share		$ 13.00
Aggregate proceeds from IPO		$ 119,300
Stock issuance, offering costs		$ 4,800
Number of shares of common stock sold		3,934,996
IPO [Member] \| Class A Common Stock [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Shares issued upon conversion		2,200,000
IPO [Member] \| Class A Common Stock [Member] \| Chief Executive Officer [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Exercise of stock options (in shares)		1,734,996
Offering [Member] \| Class A Common Stock [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of shares issued and sold	4,056,004
Number of shares of common stock sold	2,307,420
Shares issued upon conversion	1,675,420
Exercise of stock options (in shares)	257,000
Price per share	$ 35.00
Proceeds from issuance of Class A common stock in follow-on offering, net of underwriting discounts and commissions	$ 135,600
Stock issuance, offering costs	400
Proceeds from exercises of stock options	$ 500
Offering [Member] \| Class A Common Stock [Member] \| Underwriters [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Shares Sold From Underwriters Allotment	763,424
Offering [Member] \| Class B Common Stock [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Conversion from Class B to Class A	1,675,420

Property and Equipment, Net

12 Months Ended

Dec. 31, 2019

Property and Equipment, Net

5. Property and equipment, net

Property and equipment consisted of the following (in thousands):

	Estimated			December 31,
	useful lives			2019		2018
Land	Indefinite			$	9,942	$	7,994
Building and improvements	5-39 years				15,512		13,120
Computer equipment and software	3-5 years				37,361		34,582
Office furniture and equipment	5-15 years				8,029		7,958
Leasehold improvements		(1	)		9,014		6,926
Right of use assets under finance leases		(1	)		2,745		—
Total property and equipment					82,603		70,580
Less: accumulated depreciation and amortization					46,306		40,427
Property and equipment, net				$	36,297	$	30,153

(1)	Shorter of lease term or estimated useful life, generally ranging from five to ten years.

The Company allocated $1.9 million to land and $1.0 million to building and improvements in connection with the acquisition of Polliwog in October 2019, as described in Note 4 – Acquisitions and disposals.

In August 2018, the Company consummated the sale of the building that was used as the headquarters for its toggled subsidiary. The building was previously recorded as a held for sale asset and had a book value of $2.1 million as of June 30, 2018. In connection with the sale of the building, the Company entered into a three-year lease back of part of the building, primarily for continued use as a distribution center for toggled’s operational needs. The Company recognized a gain of $4.4 million which is included in other operating income for the year ended December 31, 2018.

Depreciation expense, including amortization of ROU assets under finance leases, was $7.1 million, $7.0 million and $6.3 million for the years ended December 31, 2019, 2018 and 2017, respectively.

Property and Equipment, Net - Summary of Property and Equipment (Parenthetical) (Detail)	12 Months Ended
	Dec. 31, 2019
Leasehold Improvements [Member] \| Minimum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life	5 years
Leasehold Improvements [Member] \| Maximum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life	10 years
Right-of-Use Assets Under Finance Leases [Member] \| Minimum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life	5 years
Right-of-Use Assets Under Finance Leases [Member] \| Maximum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life	10 years

Financial Instruments - Additional Information (Detail)	12 Months Ended
Financial Instruments - Additional Information (Detail)	Dec. 31, 2019 USD ($) Instrument	Dec. 31, 2018 USD ($)
Derivative [Line Items]
Derivative number of instruments outstanding \| Instrument	0
Interest Rate Swap [Member]
Derivative [Line Items]
Derivatives outstanding notional value	$ 0	$ 4,500,000
Derivatives maturity date	Dec. 23, 2019
Foreign Exchange Contract [Member]
Derivative [Line Items]
Derivatives outstanding notional value	$ 0	$ 0

Stock-based Compensation - Summary of Stock Option Activity under 2012 Plan (Detail) - 2012 Plan [Member] - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Number of options, Outstanding, Beginning Balance	1,541,165
Number of options, Granted	0
Number of options, Exercised	(348,376)
Number of options, Forfeited	(8,972)
Number of options, Outstanding, Ending Balance	1,183,817	1,541,165
Number of options, Exercisable	893,349
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Weighted average exercise price per share, Outstanding, Beginning Balance	$ 4.12
Weighted average exercise price per share, Granted	0
Weighted average exercise price per share, Exercised	3.73
Weighted average exercise price per share, Forfeited	4.64
Weighted average exercise price per share, Outstanding, Ending Balance	4.23	$ 4.12
Weighted average exercise price per share, Exercisable	$ 3.96
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted average remaining contractual term (years), Outstanding	6 years 1 month 6 days	6 years 10 months 24 days
Weighted average remaining contractual term (years), Exercisable	5 years 8 months 12 days
Aggregate intrinsic value, Outstanding		$ 36.2
Aggregate intrinsic value, Exercisable	$ 37.5

Other Liabilities - Summary of Other Accrued Expenses and Current Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Other Liabilities Disclosure [Abstract]
Income taxes payable	$ 6,008	$ 3,932
Accrued VAT	5,312	4,536
Accrued professional fees	2,581	3,165
Accrued royalties	2,314	2,613
Defined contribution plan liabilities	1,593	1,376
Obligations for acquisition of businesses	1,362	1,218
Non-income tax liabilities	1,253	853
Billings in excess of cost	879	1,504
Other current liabilities	7,301	7,842
Total	$ 28,603	$ 27,039

Segment Information - Reconciliation of U.S. GAAP Income (Loss) Before Income Taxes to Adjusted EBITDA (Parenthetical) (Detail) - USD ($) $ in Millions		3 Months Ended	12 Months Ended
	Dec. 13, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Nonrecurring acquisition related costs			$ 0.6
Nonrecurring severance expenses			0.4
Impairment charge recognized in non-recurring adjustment for royalty contracts			$ 1.0
Impairment charge recognized in non-recurring adjustment for royalty contracts and trade names				$ 2.8
Income recognized in non-recurring adjustment for change in estimated legal expenses		$ 2.0		2.0	$ 2.0
Building [Member]
Segment Reporting Information [Line Items]
Gain on sale of building				4.4
Datawatch Corporation [Member]
Segment Reporting Information [Line Items]
Nonrecurring acquisition related costs	$ 0.5
Nonrecurring costs from acquisition				$ 10.4

Summary of Significant Accounting Policies - Schedule of Accounts Receivable Net (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Accounts Notes Loans And Financing Receivable Gross Allowance And Net [Abstract]
Accounts receivable, trade	$ 100,461	$ 93,073
Contract assets	4,523	3,730
Accounts receivable, net	$ 104,984	$ 96,803

Goodwill and Other Intangible Assets - Additional Information (Detail) - USD ($)
$ in Thousands

12 Months Ended

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

Goodwill And Intangible Assets Disclosure [Abstract]

Amortization of intangible assets

$ 14,442

$ 7,739

$ 5,448

^[1]

[1]	The year ended December 31, 2017 has been reported under ASC 605 and has not been adjusted under the modified retrospective approach of ASC 606. See Note 3 – Revenue from contracts with customers for the effect of the adoption of ASC 606 on the Company’s consolidated financial statements.

Income Taxes

12 Months Ended

Dec. 31, 2019

Components of Accumulated Other Comprehensive Loss

Income Taxes

14. Income taxes

The components of income (loss) before income taxes are as follows (in thousands):

	Year ended December 31,
	2019			2018		2017
U.S.	$	(14,732	)	$	4,228	$	(49,761	)
Non-U.S.		18,120			22,796		13,350
	$	3,388		$	27,024	$	(36,411	)

The significant components of the income tax expense are as follows (in thousands):

	Year ended December 31,
	2019			2018			2017
Current
U.S. Federal	$	—		$	2		$	—
Non-U.S.		11,434			12,629			10,290
U.S. State and Local		446			(16	)		135
Total current		11,880			12,615			10,425
Deferred
U.S. Federal		193			1,714			54,130
Non-U.S.		(1,143	)		(2,823	)		1,228
U.S. State and Local		-			(17	)		(253	)
Total deferred		(950	)		(1,126	)		55,105
Income tax expense	$	10,930		$	11,489		$	65,530

The reconciliation of income taxes calculated at the U.S. Federal statutory income tax rate to income tax expense is as follows (in thousands):

	Year ended December 31,
	2019			2018			2017
U.S. federal statutory rate		21	%		21	%		35	%
Income taxes at U.S. federal statutory rate	$	711		$	5,675		$	(12,744	)
Foreign income taxes at rates other than the federal statutory rate		1,247			2,179			373
U.S. state and local income taxes, net of U.S. federal tax benefit		(6,836	)		(3,453	)		(155	)
U.S. Tax Cut and Jobs Act: transition tax, net of foreign tax credits		—			—			4,187
U.S. effect of foreign operations		8,609			—			—
Change in valuation allowance		18,138			21,544			49,859
Foreign withholding taxes		5,975			5,103			4,181
U.S. foreign tax credit		(7,059	)		(5,648	)		(4,154	)
Research and development tax credit		(2,600	)		(2,819	)		(2,999	)
Stock-based compensation		(4,574	)		(14,964	)		10,871
Meals & entertainment		246			181			358
Other		(1,068	)		1,206			(59	)
Uncertain tax positions		(1,859	)		903			446
Acquisition costs		—			503			—
Tax law changes		—			1,079			15,366
Income tax expense	$	10,930		$	11,489		$	65,530

The Tax Cuts and Jobs Act, or the Tax Act, was enacted on December 22, 2017. The Tax Act reduced the U.S. federal corporate income tax rate from 35% to 21%, required companies to pay a one-time transition tax on earnings of certain foreign subsidiaries that were previously tax deferred and created new taxes on certain foreign sourced earnings. The Company applied the guidance in Staff Accounting Bulletin No. 118, Income Tax Accounting Implications of the Tax Cut and Jobs Act when accounting for the enactment-date effects of the Tax Act. At December 31, 2018, the Company had completed its accounting for the tax effects of the Tax Act; the Company did not record any adjustments to the provisional amounts recorded at December 31, 2017 related to the remeasurement of its deferred balances. At December 31, 2017, the Company originally recorded a provisional amount for its one-time transition tax of $4.2 million, which was substantially offset by available foreign tax credits. During the year ended December 31, 2018, the Company revised its estimate of the provisional amount of the one-time transition tax. Upon further analyses of certain aspects of the Tax Act and

refinement of its calculations, the Company increased its provisional amount of transition tax by approximately $0.6 million for the year ended December 31, 2018. This resulted in no change to income tax expense due to the impact of foreign tax credits.

The Tax Act subjects a U.S. shareholder to current tax on global intangible low-taxed income (“GILTI”) earned by certain foreign subsidiaries. The impact of GILTI resulted in no incremental tax expense for the year ended December 31, 2019 due to a full valuation allowance on U.S. net deferred tax assets. In addition, the Company has made an accounting policy election to treat taxes due under the GILTI provision as a current period expense.

Deferred income tax assets and liabilities result from differences in the basis of assets and liabilities for tax and financial statements purposes. The approximate tax effect of each type of temporary difference, and operating losses and tax credit carryforwards that give rise to a significant portion of the deferred tax assets and liabilities are as follows (in thousands):

	December 31,
	2019			2018
Deferred tax assets:
Deferred revenue	$	11,408		$	1,962
Net operating loss carryforwards		38,745			38,179
Tax credit carryforwards		38,981			31,600
Stock-based compensation		6,480			6,858
Capitalized research and development		7,162			8,266
Lease obligation		7,579			—
Employee benefits		5,189			4,756
Other		1,968			1,999
Total gross deferred tax assets		117,512			93,620
Less: valuation allowances		(84,356	)		(78,155	)
Net deferred tax assets⁽¹⁾		33,156			15,465
Deferred tax liabilities:
Property and equipment and intangibles		13,588			13,966
Deferred tax on investment in subsidiary		474			329
Lease right of use asset		7,247			—
Convertible debt, net of issuance costs		10,899			—
Other		1,432			1,154
Total deferred tax liabilities		33,640			15,449
Total net deferred tax (liabilities) assets	$	(484	)	$	16

(1)	Reflects gross amount before jurisdictional netting of deferred tax assets and liabilities.

Deferred tax assets and liabilities are determined separately for each tax jurisdiction on a separate or on a consolidated tax filing basis, as applicable, in which the Company conducts its operations or otherwise incurs taxable income or losses. A valuation allowance is recorded when it is more likely than not that some portion or all of the gross deferred tax assets will not be realized. The realization of deferred tax assets depends on the ability to generate sufficient taxable income of the appropriate character within the carryback or carryforward periods provided for in the tax law for each applicable tax jurisdiction. The Company considers the following possible sources of taxable income when assessing the realization of deferred tax assets:

•

taxable income in prior carryback years;

•

future reversals of existing taxable temporary differences;

•

future taxable income exclusive of reversing temporary differences and carryforwards; and

•

prudent and feasible tax planning strategies that the Company would be willing to undertake to prevent a deferred tax asset from otherwise expiring.

The assessment regarding whether a valuation allowance is required or whether a change in judgment regarding the valuation allowance has occurred also considers all available positive and negative evidence, including but not limited to:

•

nature, frequency, and severity of cumulative losses in recent years;

•

duration of statutory carryforward and carryback periods;

•

statutory limitations against utilization of tax attribute carryforwards against taxable income;

•

historical experience with tax attributes expiring unused; and

•

near‑ and medium‑term financial outlook.

The weight given to the positive and negative evidence is commensurate with the extent to which the evidence may be objectively verified. Accordingly, it is generally difficult to conclude a valuation allowance is not required when there is significant objective and verifiable negative evidence, such as cumulative losses in recent years. The Company uses the actual results for the last two years and current year results as the primary measure of cumulative losses in recent years.

The evaluation of deferred tax assets requires judgment in assessing the likely future tax consequences of events recognized in the financial statements or tax returns and future profitability. The recognition of deferred tax assets represents the Company’s best estimate of those future events. Changes in the current estimates, due to unanticipated events or otherwise, could have a material effect on the Company’s results of operations and financial condition.

In certain tax jurisdictions, the Company’s analysis indicates that it has cumulative losses in recent years. This is considered significant negative evidence, which is objective and verifiable and, therefore, difficult to overcome. However, the cumulative loss position is not solely determinative and, accordingly, the Company considers all other available positive and negative evidence in its analysis. Based on its analysis, the Company has recorded a valuation allowance for the portion of deferred tax assets where based on the weight of available evidence it is unlikely to realize those deferred tax assets.

Based on the evidence available including a lack of sustainable earnings, the Company in its judgment previously recorded a valuation allowance against substantially all of its net deferred tax assets in the United States. If a change in judgment regarding this valuation allowance were to occur in the future, the Company will record a potentially material deferred tax benefit, which could result in a favorable impact on the effective tax rate in that period.

As a result of the Tax Act, the Company has not had a change in judgement regarding the gross book-tax basis differences in its non-U.S. consolidated subsidiaries. The Tax Act required a one-time transition tax for deemed repatriation of accumulated undistributed earnings of certain foreign investments. If we determine that all or a portion of our foreign earnings are no longer indefinitely reinvested, we may be subject to additional foreign withholding taxes, U.S. taxes on foreign currency fluctuations on these accumulated undistributed earnings, and incremental U.S. state income taxes, beyond the Tax Act's one-time transition tax. The Company continues to record deferred foreign taxes on gross book-tax basis differences to the extent of foreign distributable reserves and excess cash balances for its subsidiary in India. Determining the amount of unrecognized deferred tax liability related to any remaining undistributed foreign earnings is not practicable.

The following table summarizes the changes to the valuation allowance balance at December 31, 2019, 2018 and 2017 (in thousands):

	December 31,
	2019			2018			2017
Beginning balance	$	78,155		$	56,761		$	4,153
Additions charged to expense		18,138			21,544			49,859
Other		(11,937	)		(150	)		2,749
Ending balance	$	84,356		$	78,155		$	56,761

The tax benefit in Other for 2019 of $11.9 million is related to the issuance of convertible debt, net of issuance costs. The tax benefit in Other for 2018 of $0.2 million is related to a tax benefit from the adoption of ASC 606 of $12.6 million, and the tax benefit recorded in other comprehensive income of $0.2 million, offset by deferred tax expense recorded for business combinations of $12.6 million.

The following table summarizes the amount and expiration dates of operating loss and tax credit carryforwards at December 31, 2019 (in thousands):

	Expiration dates	Amounts
U.S. general business credits and loss carryforwards	2020-Indefinite	$	56,073
Foreign loss carryforwards	Indefinite		9,182
U.S. foreign tax credits	2027		12,471
Total operating loss and tax credit carryforwards		$	77,726

A reconciliation of the beginning and ending amounts of unrecognized tax benefits is as follows (in thousands):

	Year ended December 31,
	2019			2018			2017
Unrecognized tax benefits—January 1	$	17,097		$	6,157		$	5,604
Increase in unrecognized tax benefits as a result of:
Additions for tax positions of current period		(203	)		234			634
Additions for tax positions of prior periods		642			10,866			—
Reductions for tax positions of prior periods		(1,834	)		(100	)		(81	)
Reductions due to statute of limitations		(162	)		(60	)		—
Unrecognized tax benefits—December 31	$	15,540		$	17,097		$	6,157

At December 31, 2019, the Company had $8.2 million of gross unrecognized tax benefits that if recognized would affect the effective tax rate. The Company expects a reduction over the next 12 months in the gross unrecognized tax benefits of approximately $0.4 million which if recognized would impact the effective tax rate during 2020.

The Company operates globally but considers its more significant tax jurisdictions to include the United States, India, Germany, Japan, and China. India has tax years open for examination from 2008 through 2018. All other significant jurisdictions have open tax years from 2014 through 2018.

The Company records interest and penalties with respect to unrecognized tax benefits as a component of the provision for income taxes. For the years ended December 31, 2019 and 2018, accrued interest and penalties related to unrecognized tax benefits were insignificant.

Accumulated Other Comprehensive Loss (Tables)

12 Months Ended

Dec. 31, 2019

Equity [Abstract]

The components of accumulated other comprehensive loss are as follows (in thousands):

	Foreign currency translation			Retirement related benefit plans			Total
Balance at December 31, 2016	$	(5,725	)	$	(1,539	)	$	(7,264	)
Other comprehensive income (loss) before reclassification		2,351			(213	)		2,138
Amounts reclassified from accumulated other comprehensive loss		—			54			54
Tax effects		—			—			—
Other comprehensive income (loss)		2,351			(159	)		2,192
Balance at December 31, 2017		(3,374	)		(1,698	)		(5,072	)
Other comprehensive income (loss) before reclassification		(5,449	)		90			(5,359	)
Amounts reclassified from accumulated other comprehensive loss		—			(1,177	)		(1,177	)
Tax effects		—			318			318
Other comprehensive income (loss)		(5,449	)		(769	)		(6,218	)
Balance at December 31, 2018		(8,823	)		(2,467	)		(11,290	)
Other comprehensive income (loss) before reclassification		1,895			62			1,957
Amounts reclassified from accumulated other comprehensive loss		—			(179	)		(179	)
Tax effects		—			(16	)		(16	)
Other comprehensive income (loss)		1,895			(133	)		1,762
Balance at December 31, 2019	$	(6,928	)	$	(2,600	)	$	(9,528	)

Property and Equipment, Net - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Oct. 31, 2019	Jun. 30, 2018
Property, Plant and Equipment [Line Items]
Book value of building held for sale, net	$ 36,297	$ 30,153
Depreciation expense, including amortization of right-of-use assets under finance leases	$ 7,100	7,000	$ 6,300
Polliwog Co. Ltd. [Member]
Property, Plant and Equipment [Line Items]
Property and equipment				$ 2,900
Land [Member] \| Polliwog Co. Ltd. [Member]
Property, Plant and Equipment [Line Items]
Property and equipment				1,900
Building and Improvements [Member] \| Polliwog Co. Ltd. [Member]
Property, Plant and Equipment [Line Items]
Property and equipment				$ 1,000
Building [Member]
Property, Plant and Equipment [Line Items]
Book value of building held for sale, net					$ 2,100
Sale leaseback transaction lease terms	three-year
Gain on sale of building		$ 4,400

Stock-Based Compensation

12 Months Ended

Dec. 31, 2019

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock-Based Compensation

13. Stock-based compensation

2001 stock-based compensation plans

Nonqualified stock option plan

In 2001, the Company established the Nonqualified Stock Option Plan (“NSO Plan”) under which 3,557,436 stock options with an exercise price of $.000025 remain outstanding at December 31, 2019. The NSO Plan was terminated in 2003. Stock options under the NSO plan were immediately vested and have a contractual term of 35 years from the date of grant. The outstanding awards will continue to be governed by their existing terms under the NSO Plan. The NSO Plan is accounted for as an equity plan.

The following table summarizes the stock option activity under the NSO Plan:

	Number of options			Weighted average exercise price per share		Weighted average remaining contractual term (years)		Aggregate intrinsic value (in millions)
Outstanding at January 1, 2019		4,337,856		$	0.000025		18.0	$	119.6
Exercised		(780,420	)	$	0.000025
Forfeited		—		$	—
Outstanding and exercisable at December 31, 2019		3,557,436		$	0.000025		17.0	$	127.8

The total intrinsic value of the NSO Plan stock options exercised during the years ended December 31, 2019, 2018 and 2017, was $28.8 million, $68.4 million and $0.4 million, respectively.

Incentive and nonqualified stock-based plan

Also, in 2001, the Company established the Incentive and Nonqualified Stock-based Plan (“ISO Plan”) which was terminated in 2011 and was authorized to issue nonqualified stock options (“NQSO”) and incentive stock options (“ISO”) totaling 11,153,872 shares of Class A common stock. The NQSO grants could be issued at less than the fair market value at date of grant under the terms of the ISO Plan, while ISO grants were issued at a price equal to or greater than the fair market value at date of grant. Options generally vest over a two to three-year period. All options have a contractual term of ten years from the date of grant. At December 31, 2019 and 2018, there were 103,000 and 532,220 options outstanding, respectively, under the ISO Plan.

As a result of the Company’s IPO in the fourth quarter 2017, the call feature terminated which resulted in the $66.5 million liability valued immediately prior to the IPO associated with the Company’s Class A redeemable common shares and with the stock options outstanding under the 2001 ISO and NQSO Plan to be reclassified to equity as of December 31, 2017 in accordance with ASC 718.

The following table summarizes the stock option activity under the 2001 Stock-based compensation plans for the periods indicated as follows:

	Number of options			Weighted average exercise price per share		Weighted average remaining contractual term (years)		Aggregate intrinsic value (in millions)
Outstanding at January 1, 2019		532,220		$	0.65		1.4	$	14.3
Exercised		(429,220	)	$	0.66
Forfeited		—		$	—
Outstanding and exercisable at December 31, 2019		103,000		$	0.64		1.0	$	3.6

The total intrinsic value of the ISO Plan stock options exercised during the years ended December 31, 2019, 2018 and 2017, was $14.4 million, $5.2 million, and $25.6 million, respectively.

2012 stock-based compensation plans

During 2012, the Company established the 2012 Incentive and Nonqualified Stock Option Plan (“2012 Plan”) which permits the issuance of 5,200,000 shares of Class A common stock for the grant of nonqualified stock options (“NQSO”) and incentive stock options (“ISO”) for management, other employees, and board members of the Company. The options are issued at a price equal to or greater than fair market value at date of grant. All options have a contractual term of 10 years from date of grant.

The 2012 Plan is accounted for as an equity plan. For those options expected to vest, compensation expense is recognized on a straight-line basis over a four-year period, the total requisite service period of the awards. Compensation expense related to the 2012 Plan was $0.4 million, $0.6 million and $0.7 million for the years ended December 31, 2019, 2018 and 2017, respectively.

The following table summarizes the stock option activity under the 2012 Plan for the periods indicated as follows:

	Number of options			Weighted average exercise price per share		Weighted average remaining contractual term (years)		Aggregate intrinsic value (in millions)
Outstanding at January 1, 2019		1,541,165		$	4.12		6.9	$	36.2
Granted		—		$	—
Exercised		(348,376	)	$	3.73
Forfeited		(8,972	)	$	4.64
Outstanding at December 31, 2019		1,183,817		$	4.23		6.1
Exercisable at December 31, 2019		893,349		$	3.96		5.7	$	37.5

The total intrinsic value of the 2012 Plan stock options exercised during the year ended December 31, 2019, was $11.2 million. Total compensation cost related to nonvested awards not yet recognized as of December 31, 2019 totaled $0.4 million and is expected to be recognized over a weighted average period of 1.1 years.

2017 stock-based compensation plan

In 2017, the Company’s board of directors adopted the 2017 Equity Incentive Plan (“2017 Plan”), which was approved by the Company’s stockholders. The 2017 Plan provides for the grant of incentive stock options to the Company’s employees and any parent and subsidiary corporations’ employees, and for the grant of nonstatutory stock options, stock appreciation rights, restricted stock, restricted stock units, performance units, performance shares, other cash-based awards and other stock-based awards to the Company’s employees, directors and consultants and the Company’s parent, subsidiary, and affiliate corporations’ employees and consultants. The 2017 Plan has 8,104,971 authorized shares of the Company’s Class A common stock reserved for issuance.

The following table summarizes the restricted stock units, or RSUs, awarded under the 2017 Plan for the period:

	Number of RSUs
Outstanding at January 1, 2019		206,061
Granted		694,690
Vested		(60,388	)
Forfeited		(59,062	)
Outstanding at December 31, 2019		781,301

The weighted average grant date fair value of the RSUs was $37.23 and the RSUs generally vest in four equal annual installments. Total compensation cost related to nonvested awards not yet recognized as of December 31, 2019, totaled $22.9 million, and is expected to be recognized over a weighted average period of 3.3 years. The fair value of RSUs that vested during the year ended December 31, 2019, was $2.2 million.

The following table summarizes the stock option activity under the 2017 Plan for the period:

	Number of options		Weighted average exercise price per share		Weighted average remaining contractual term (years)		Aggregate intrinsic value (in millions)
Outstanding at January 1, 2019		—	$	—		—		—
Granted		20,000	$	38.11
Exercised		—	$	—
Forfeited		—	$	—
Outstanding at December 31, 2019		20,000	$	38.11		9.2
Exercisable at December 31, 2019		—

Fair value of equity awards

The Company measures the fair value of its stock options on the date of grant using the Black-Scholes option pricing model. This valuation model requires the Company to make certain estimates and assumptions, including assumptions related to the expected price volatility of the Company’s stock, the period under which the options will be outstanding, the rate of return on risk-free investments, and the expected dividend yield for the Company’s stock.

The fair values of the Company’s stock options granted during the year ended December 31, 2019 and 2017, were estimated using the following assumptions:

	2019 grants			2017 grants
Weighted average grant date fair value per share	$	38.11		$1.86 - $1.94
Expected volatility		42	%		34	%
Expected term (in years)		6.25		5.75-6.25
Risk-free interest rate		1.80	%		2.02	%
Expected dividend yield		0	%		0	%

These assumptions and estimates are as follows:

•

Fair Value of Common Stock. The Company used the publicly quoted price as reported on the Nasdaq Global Select Market as the fair value of its common stock.

•

Expected Term. The Company used the simplified method to determine the expected term.

•

Risk-Free Interest Rate. The Company based the risk-free interest rate on U.S. Treasury zero-coupon yield curves with a remaining term equal to the expected term of the option.

•

Expected Volatility. As the Company does not have an extensive trading history for its common stock, the expected volatility was derived using the historical volatility of the returns of comparable publicly traded companies combined with the brief trading history of the Company’s common stock.

The Company did not grant any stock options during the year ended December 31, 2018.

Other

In connection with the acquisition of Polliwog, per the Stock Purchase Agreement, 256,594 shares of the Company’s Class A Common Stock will be issued to existing employees, subject to continuing employment. The shares will be issued on the one-, two- and three-year anniversaries of the closing, subject to potential reduction in certain circumstances. The accounting treatment for these shares in the context of the business combination is to recognize the expense as a post-combination expense, not as transaction consideration.

The estimated post combination expense to the Company as a result of the business combination was approximately $8.7 million which will be recognized on a straight-line basis over the remaining employment period that was stipulated in the Stock Purchase Agreement. The weighted average remaining service period is 2.8 years. Once the vesting conditions of the service period are met, the Company will issue shares for each award. Stock-based compensation expense includes approximately $0.7 million expense related to these shares for the year ended December 31, 2019.

In connection with the acquisition of Datawatch, all outstanding unvested Datawatch RSUs were converted into a right to receive cash (the “Replacement Awards”). The payment to the holders of unvested Datawatch RSUs will be payable on or after the date that such RSUs would have otherwise vested in accordance with its original terms.

The accounting treatment for the outstanding unvested Datawatch RSUs in the context of the business combination is to allocate the fair value of the RSU’s at the date of consummation attributable to pre-combination service to the aggregate merger consideration. The difference between the fair value of the Replacement Awards and the amount allocable to pre-combination service was considered a post-combination expense to the Company after the consummation date.

The estimated post combination expense to the Company as a result of the business combination was approximately $3.4 million which will be recognized on a straight-line basis over the remaining service period that was stipulated in each holder’s original RSU agreement. The weighted average remaining service period is 0.6 years. Once the vesting conditions of the service period are met, Altair will cash-settle the Replacement Awards. The liability related to the Datawatch RSUs as of December 31, 2019 and 2018, was $0.5 million and $0.6 million, respectively, and is recorded in other accrued expenses and current liabilities.

In connection with the acquisition of Runtime Design Automation (“RTDA”), all outstanding stock options of RTDA became fully vested and exercisable prior to the date of consummation which represents an acceleration to full vesting of all unvested stock options as of the date of the business combination.

The accounting treatment for the outstanding stock options in the context of the business combination is to allocate the fair market value of RTDA’s options at the date of consummation attributable to pre-combination service to the aggregate merger consideration. The difference between the fair market value of the replacement awards and the amount allocable to pre-combination service was considered a post-combination expense to the Company after the consummation date.

The estimated post combination expense to the Company as a result of the business combination was approximately $2.0 million which was immediately expensed in the post combination financial statements in the third quarter of 2017, as there were no further service conditions. The Company determined that the Black-Scholes model was an appropriate valuation model for the employee share options as all of RTDA’s stock options had only service conditions.

Stock-based compensation expense

The stock-based compensation expense was recorded as follows (in thousands):

	Year ended December 31,
	2019		2018		2017
Cost of revenue-software	$	1,069	$	31	$	350
Research and development		2,917		740		12,540
Sales and marketing		2,250		910		7,693
General and administrative		2,292		1,658		26,698
Total stock-based compensation expense	$	8,528	$	3,339	$	47,281

Summary of Significant Accounting Policies - Effect of Error Correction on Company's Financial Statements (Detail) - USD ($)
$ / shares in Units, $ in Thousands

3 Months Ended

12 Months Ended

Dec. 31, 2019

Sep. 30, 2019

Jun. 30, 2019

Mar. 31, 2019

Dec. 31, 2018

Sep. 30, 2018

Jun. 30, 2018

Mar. 31, 2018

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

Effect of error correction on Balance Sheet [Abstract]

Deferred tax assets

$ 5,791

$ 5,354

$ 5,791

$ 5,354

Total assets

743,145

487,197

743,145

487,197

Other accrued expenses and current liabilities

28,603

27,039

28,603

27,039

Total current liabilities

152,866

127,232

152,866

127,232

Other long-term liabilities

26,672

25,756

26,672

25,756

Total liabilities

386,086

191,159

386,086

191,159

Accumulated deficit

(82,405)

(74,863)

(82,405)

(74,863)

Accumulated other comprehensive loss

(9,528)

(11,290)

(9,528)

(11,290)

Total stockholders' equity

354,707

293,686

354,707

293,686

Total liabilities, mezzanine equity and stockholders' equity

743,145

487,197

743,145

487,197

Effect of error corrections on statements of operations [Abstract]

3,388

27,024

$ (36,411)

^[1]

10,930

11,489

65,530

^[1]

Net income (loss) per share attributable to common stockholders, basic

$ (1,502)

$ (15,939)

$ (3,120)

$ 13,019

$ (9,003)

$ 934

$ (1,080)

$ 24,684

$ (7,542)

$ 15,535

$ (101,941)

^[1]

$ (0.02)

$ (0.22)

$ (0.04)

$ 0.18

$ (0.13)

$ 0.01

$ (0.02)

$ 0.39

$ (0.11)

$ 0.23

$ (1.94)

^[1]

Net income (loss) per share attributable to common stockholders, diluted

$ (0.02)

$ (0.22)

$ (0.04)

$ 0.17

$ (0.13)

$ 0.01

$ (0.02)

$ 0.34

$ (0.11)

$ 0.21

$ (1.94)

^[1]

As Reported [Member]

Effect of error correction on Balance Sheet [Abstract]

Deferred tax assets

$ 1,373

Total assets

483,216

Other accrued expenses and current liabilities

27,565

Total current liabilities

127,758

Other long-term liabilities

28,153

Total liabilities

194,082

Accumulated deficit

(82,005)

Accumulated other comprehensive loss

(11,052)

Total stockholders' equity

286,782

Total liabilities, mezzanine equity and stockholders' equity

483,216

Effect of error corrections on statements of operations [Abstract]

27,024

$ (36,411)

13,309

62,996

Net income (loss) per share attributable to common stockholders, basic

$ 13,715

$ (99,407)

$ 0.20

$ (1.89)

Net income (loss) per share attributable to common stockholders, diluted

$ 0.18

$ (1.89)

Adjustments [Member]

Effect of error correction on Balance Sheet [Abstract]

Deferred tax assets

3,981

$ 3,981

Total assets

3,981

Other accrued expenses and current liabilities

(526)

Total current liabilities

(526)

Other long-term liabilities

(2,397)

Total liabilities

(2,923)

Accumulated deficit

7,142

Accumulated other comprehensive loss

(238)

Total stockholders' equity

6,904

Total liabilities, mezzanine equity and stockholders' equity

$ 3,981

3,981

Effect of error corrections on statements of operations [Abstract]

(1,820)

$ 2,534

Net income (loss) per share attributable to common stockholders, basic

$ 1,820

$ (2,534)

$ 0.03

$ (0.05)

Net income (loss) per share attributable to common stockholders, diluted

$ 0.03

$ (0.05)

[1]	The year ended December 31, 2017 has been reported under ASC 605 and has not been adjusted under the modified retrospective approach of ASC 606. See Note 3 – Revenue from contracts with customers for the effect of the adoption of ASC 606 on the Company’s consolidated financial statements.

Summary of Significant Accounting Policies - Schedule of Other Income, Net (Detail) - USD ($)
$ in Thousands

12 Months Ended

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

Foreign exchange loss (gain)

$ 745

$ (626)

$ 1,254

Other

(2,297)

(1,954)

(260)

Other (income) expense, net

$ (1,552)

$ (2,580)

$ 994

^[1]

[1]	The year ended December 31, 2017 has been reported under ASC 605 and has not been adjusted under the modified retrospective approach of ASC 606. See Note 3 – Revenue from contracts with customers for the effect of the adoption of ASC 606 on the Company’s consolidated financial statements.

Income Taxes - Components of Income (Loss) Before Income Taxes (Detail) - USD ($)
$ in Thousands

12 Months Ended

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

U.S

$ (14,732)

$ 4,228

$ (49,761)

Non-U.S

18,120

22,796

13,350

Quarterly Financial Information Disclosure [Abstract]

$ 3,388

$ 27,024

$ (36,411)

^[1]

[1]	The year ended December 31, 2017 has been reported under ASC 605 and has not been adjusted under the modified retrospective approach of ASC 606. See Note 3 – Revenue from contracts with customers for the effect of the adoption of ASC 606 on the Company’s consolidated financial statements.

Revenue from Contracts with Customers - Additional Information (Detail) - USD ($) $ in Thousands		12 Months Ended
	Jan. 01, 2018	Dec. 31, 2019	Dec. 31, 2018
Revenue From Contracts With Customers [Line Items]
Cumulative effect on accumulated deficit, before tax	$ 84,600
Cumulative effect on accumulated deficit, net of tax	77,700
Accumulated deficit		$ (82,405)	$ (74,863)
Capitalized contract cost, amortization period		4 years
Capitalized contract cost, amortization method		straight-line basis
Contract assets		$ 4,523	3,730
Deferred revenue, revenue recognized		57,800
Sales and Marketing Expense [Member]
Revenue From Contracts With Customers [Line Items]
Capitalized contract cost, amortization expense		4,500	300
Prepaid and Other Current Assets [Member]
Revenue From Contracts With Customers [Line Items]
Capitalized contract cost net, current		2,300	2,000
Contract assets		2,700	2,700
Other Long-Term Assets [Member]
Revenue From Contracts With Customers [Line Items]
Capitalized contract cost net, noncurrent		800	200
Accounts Receivable [Member]
Revenue From Contracts With Customers [Line Items]
Contract assets		$ 4,500	$ 3,700
ASC 606 [Member]
Revenue From Contracts With Customers [Line Items]
Accumulated deficit	$ 82,900
Percentage of net revenues through indirect channels		10.00%	10.00%

Supplemental Quarterly Financial Information (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2019

Summary of Quarterly Financial Information

The following tables set forth selected unaudited quarterly information. The information for each of these quarters has been prepared on the same basis as the audited annual consolidated financial statements and, in the opinion of management, includes all adjustments, which consist only of normal recurring adjustments, necessary for the fair presentation of the results of operations for these periods in accordance with GAAP. This data should be read in conjunction with the Company’s audited consolidated financial statements and

related notes. These quarterly operating results are not necessarily indicative of the Company’s operating results for a full year or any future period.

	Three months ended
(in thousands, except per share data)	March 31, 2019		June 30, 2019			September 30, 2019			December 31, 2019
Total revenue	$	127,859	$	106,773		$	100,406		$	123,877
Gross profit	$	94,974	$	75,750		$	68,665		$	86,927
Operating income (loss)	$	17,767	$	(3,202	)	$	(10,507	)	$	4,149
Net income (loss)	$	13,019	$	(3,120	)	$	(15,939	)	$	(1,502	)
Net income (loss) per share, basic	$	0.18	$	(0.04	)	$	(0.22	)	$	(0.02	)
Net income (loss) per share, diluted	$	0.17	$	(0.04	)	$	(0.22	)	$	(0.02	)

	Three months ended
(in thousands, except per share data)	March 31, 2018		June 30, 2018			September 30, 2018		December 31, 2018
Total revenue	$	113,257	$	93,360		$	86,751	$	103,011
Gross profit	$	84,215	$	63,904		$	59,547	$	72,740
Operating income (loss)	$	26,146	$	175		$	1,880	$	(3,557	)
Net income (loss)	$	24,684	$	(1,080	)	$	934	$	(9,003	)
Net income (loss) per share, basic	$	0.39	$	(0.02	)	$	0.01	$	(0.13	)
Net income (loss) per share, diluted	$	0.34	$	(0.02	)	$	0.01	$	(0.13	)

Acquisitions and Disposals - Summary of Amounts of Identified Assets Acquired and Liabilities Assumed at the Acquisition Date (Parenthetical) (Detail) - Datawatch Corporation [Member] $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($)
Software [Member]
Business Acquisition [Line Items]
Goodwill deductible for tax purposes	$ 0.8
Developed Technology [Member]
Business Acquisition [Line Items]
Weighted-average useful life of acquired finite-lived intangible assets	6 years
Customer Relationships [Member]
Business Acquisition [Line Items]
Weighted-average useful life of acquired finite-lived intangible assets	10 years

Debt - Additional Information (Detail)		1 Months Ended	12 Months Ended
Debt - Additional Information (Detail)	Jun. 05, 2019 USD ($)	Jun. 30, 2019 USD ($) d $ / shares shares	Dec. 31, 2019 USD ($) $ / shares	Dec. 31, 2018 USD ($)
Debt Instrument [Line Items]
Debt instrument, equity component recorded in additional paid-in capital			$ 50,009,000
Overdraft and Line of Credit [Member]
Debt Instrument [Line Items]
Loan outstanding			0	$ 0
Amount available under secured credit agreement			$ 3,500,000	$ 3,500,000
Convertible Senior Notes Due in 2024 [Member]
Debt Instrument [Line Items]
Debt instrument, aggregate principal amount		$ 230,000,000.0
Debt instrument interest rate		0.25%
Additional principal amount of notes to underwriters		$ 30,000,000.0
Net proceeds from issuance of costs		$ 221,900,000
Debt instrument frequency of periodic payment			semi-annually
Interest payment commencement date		Dec. 01, 2019
Debt instrument maturity date		Jun. 01, 2024
Debt instrument, description			The Convertible Notes bear interest at a rate of 0.25% per year, payable semi-annually in arrears on June 1 and December 1 of each year, commencing December 1, 2019.
Debt instrument conversion rate principal amount of notes		$ 1,000
Debt instrument, convertible, terms of conversion feature			The Convertible Notes have an initial conversion rate of 21.5049 shares of the Company's Class A common stock per $1,000 principal amount of Convertible Notes, which is equivalent to an initial conversion price of approximately $46.50 per share of its Class A common stock.
Debt instrument, convertible, discount rate		5.50%
Debt instrument, fair value of the liability component		$ 178,200,000
Debt instrument, equity component recorded in additional paid-in capital		$ 51,800,000
Issuance costs attributable to liability component			$ 6,300,000
Issuance costs attributable to equity component			$ 1,800,000
Convertible Senior Notes Due in 2024 [Member] \| Class A Common Stock [Member]
Debt Instrument [Line Items]
Debt conversion, converted instrument, shares issued \| shares		21.5049
Debt instrument conversion rate principal amount of notes		$ 1,000
Debt instrument convertible initial conversion price per share of common stock \| $ / shares		$ 46.50	$ 46.50
Convertible Senior Notes Due in 2024 [Member] \| Class A Common Stock [Member] \| Convertible Notes, Holders Conversion Rights, Circumstances 1 [Member]
Debt Instrument [Line Items]
Debt instrument, convertible, consecutive trading days \| d		30
Convertible Senior Notes Due in 2024 [Member] \| Class A Common Stock [Member] \| Convertible Notes, Holders Conversion Rights, Circumstances 1 [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Debt instrument, convertible, trading days \| d		20
Debt instrument, convertible, threshold percentage of conversion price		130.00%
Convertible Senior Notes Due in 2024 [Member] \| Class A Common Stock [Member] \| Convertible Notes, Holders Conversion Rights, Circumstances 2 [Member]
Debt Instrument [Line Items]
Debt instrument conversion rate principal amount of notes		$ 1,000
Debt instrument, convertible, consecutive trading days \| d		5
Debt instrument, convertible, business days \| d		5
Debt instrument, convertible, maximum threshold percentage of sale price of common stock during measurement period		98.00%
Twenty Nineteen Credit Agreement
Debt Instrument [Line Items]
Maturity date	Dec. 15, 2023
Credit facility	$ 150,000,000.0
Increase in line of credit borrowing capacity	50,000,000.0
Increase in unrestricted domestic cash	$ 20,000,000.0
Maximum leverage ratio	5.00%
Twenty Nineteen Credit Agreement \| Federal Funds Effective Swap Rate [Member]
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	0.50%
Twenty Nineteen Credit Agreement \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	1.00%
Twenty Nineteen Credit Agreement \| Minimum [Member]
Debt Instrument [Line Items]
Commitment fees on unused portion of the Revolving Credit Facility			0.15%
EBITDA to cash Consolidated Interest Expense ratio	3.00%
Twenty Nineteen Credit Agreement \| Minimum [Member] \| Eurodollar Loans [Member]
Debt Instrument [Line Items]
Applicable margin for borrowings under new credit facility	1.25%
Twenty Nineteen Credit Agreement \| Minimum [Member] \| Swingline Loans [Member]
Debt Instrument [Line Items]
Applicable margin for borrowings under new credit facility	0.25%
Twenty Nineteen Credit Agreement \| Minimum [Member] \| APR Loans [Member]
Debt Instrument [Line Items]
Applicable margin for borrowings under new credit facility	0.25%
Twenty Nineteen Credit Agreement \| Maximum [Member]
Debt Instrument [Line Items]
Commitment fees on unused portion of the Revolving Credit Facility			0.30%
Senior secured leverage ratio	3.00%
Twenty Nineteen Credit Agreement \| Maximum [Member] \| Eurodollar Loans [Member]
Debt Instrument [Line Items]
Applicable margin for borrowings under new credit facility	2.00%
Twenty Nineteen Credit Agreement \| Maximum [Member] \| Swingline Loans [Member]
Debt Instrument [Line Items]
Applicable margin for borrowings under new credit facility	1.00%
Twenty Nineteen Credit Agreement \| Maximum [Member] \| APR Loans [Member]
Debt Instrument [Line Items]
Applicable margin for borrowings under new credit facility	1.00%
Secured Credit Agreement [Member]
Debt Instrument [Line Items]
Loan outstanding			$ 0
Amount available for future borrowing			$ 150,000,000.0
Weighted Average Interest Rate on borrowings			0.36%

(Loss) Income Per Share - Computation of Numerators and Denominators Used in Basic and Diluted (Loss) Income Per Share Amounts (Detail) - USD ($)
$ / shares in Units, shares in Thousands, $ in Thousands

3 Months Ended

12 Months Ended

Dec. 31, 2019

Sep. 30, 2019

Jun. 30, 2019

Mar. 31, 2019

Dec. 31, 2018

Sep. 30, 2018

Jun. 30, 2018

Mar. 31, 2018

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

^[1]

Numerator:

Denominator for basic (loss) income per share— weighted average shares

$ (1,502)

$ (15,939)

$ (3,120)

$ 13,019

$ (9,003)

$ 934

$ (1,080)

$ 24,684

$ (7,542)

$ 15,535

$ (101,941)

Denominator:

71,544

67,468

52,466

Effect of dilutive securities, stock options and RSUs

7,410

Denominator for dilutive (loss) income per share

71,544

74,878

52,466

Net (loss) income per share attributable to common stockholders, basic

$ (0.02)

$ (0.22)

$ (0.04)

$ 0.18

$ (0.13)

$ 0.01

$ (0.02)

$ 0.39

$ (0.11)

$ 0.23

$ (1.94)

Net (loss) income per share attributable to common stockholders, diluted

$ (0.02)

$ (0.22)

$ (0.04)

$ 0.17

$ (0.13)

$ 0.01

$ (0.02)

$ 0.34

$ (0.11)

$ 0.21

$ (1.94)

[1]	The year ended December 31, 2017 has been reported under ASC 605 and has not been adjusted under the modified retrospective approach of ASC 606. See Note 3 – Revenue from contracts with customers for the effect of the adoption of ASC 606 on the Company’s consolidated financial statements.

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04(19))
-URI http://asc.fasb.org/extlink&oid=116637232&loc=SL114874131-224263

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+ Details

The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

+ References

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+ Details

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

Revenues from External Customers and Long-Lived Assets [Line Items]

Leases

12 Months Ended

Dec. 31, 2019

Leases [Abstract]

Leases

8. Leases

The Company determines if an arrangement is a lease at inception. Operating leases are included in operating lease assets and operating lease obligations on the Company’s consolidated balance sheets. Finance leases are included in property and equipment, current portion of long-term debt, and long-term debt on the consolidated balance sheets.

ROU assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the Company’s obligation to make lease payments under the lease. Operating lease ROU assets and operating lease liabilities are recognized based on the present value of the future minimum lease payments over the lease term at commencement date. At commencement date, the ROU asset also includes adjustments for lease prepayments, lease incentives received and the lessee's initial direct costs, if applicable. As most of the Company’s leases do not provide an implicit rate, the Company uses its incremental borrowing rate based on the information available at commencement date in determining the present value of future payments. The incremental borrowing rates are determined using rates specific to the term of the lease, economic environments where lease activity is concentrated, value of lease portfolio, and assuming full collateralization of the loans. Subsequent to the commencement date, the operating ROU asset is equal to the remeasured lease liability adjusted for cumulative prepaid or accrued rent if the lease payments are uneven throughout the lease term, unamortized lease incentives, unamortized initial direct costs and any impairment of the ROU assets. The lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option. Lease cost for minimum lease payments is recognized on a straight-line basis over the lease term.

The Company has elected not to recognize a lease liability or ROU asset for short-term leases (leases with a term of twelve months or less). For contracts with lease and non-lease components, the Company has elected not to allocate the contract consideration, and account for the lease and non-lease components as a single lease component.

The Company’s operating leases consist of office facilities, office equipment and cars and the Company’s finance leases consist of office equipment and cars. The Company’s leases have remaining terms of less than one year to 7.9 years, some of which include one or more options to renew, with renewal terms up to six years and some of which include options to terminate the leases within the next four years.

The components of lease cost were as follows (in thousands):

	For the Year Ended December 31,
	2019
Operating lease cost	$	13,287

Finance lease cost:
Amortization of ROU assets	$	525
Interest on lease liabilities		21
Total finance lease cost	$	546

Operating lease cost includes short-term leases and variable lease costs, which are immaterial. Rent cost related to operating leases for office facilities was $11.8 million, $11.0 million and $9.9 million for the years ended December 31, 2019, 2018 and 2017, respectively.

Supplemental balance sheet information related to lease liabilities at December 31, 2019, was as follows:

(in thousands, except lease term and discount rate)
Operating leases:
Operating lease ROU assets	$	28,134

Current portion of operating lease liabilities	$	9,141
Operating lease liabilities, net of current portion		20,174
Total operating lease liabilities	$	29,315

Weighted average remaining lease term	4.2
Weighted average discount rate		5.6	%

Finance leases:
Property and equipment	$	2,745
Accumulated depreciation		(1,447	)
Property and equipment, net	$	1,298

Current portion of long-term debt	$	430
Long-term debt, net of current portion		744
Total finance lease liabilities	$	1,174

Weighted average remaining lease term		2.7
Weighted average discount rate		3.5	%

Supplemental cash flow information related to leases for the year ended December 31, 2019, was as follows (in thousands):

Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$	(11,355	)
Operating cash flows from finance leases	$	(46	)
Financing cash flows from finance leases	$	(438	)

ROU assets obtained in exchange for lease obligations:
Operating leases	$	11,251
Finance leases	$	632

Maturities of operating lease liabilities at December 31, 2019, were as follows (in thousands):

Year ending December 31,
2020	$	10,444
2021		8,177
2022		5,768
2023		3,684
2024		1,730
Thereafter		3,055
Total lease payments		32,858
Less: imputed interest		3,543
Total operating lease liabilities	$	29,315

Total obligations for finance leases, previously referred to as capital leases prior to the adoption of Topic 842 on January 1, 2019, were $0.8 million at December 31, 2018.

Other Liabilities - Summary of Other Long-term Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Other Liabilities Disclosure [Abstract]
Pension and other post retirement liabilities	$ 10,379	$ 9,111
Deferred tax liabilities	6,275	5,339
Other liabilities	10,018	11,306
Total	$ 26,672	$ 25,756

Segment Information - Summary of Sales to External Customers and Long-Lived Assets by Geographical Areas (Detail) - USD ($)
$ in Thousands

12 Months Ended

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

$ 458,915

$ 396,379

$ 333,333

Revenues from External Customers and Long-Lived Assets [Line Items]

92,431

90,332

^[1]

United States [Member]

219,053

186,026

142,679

Other American Countries [Member]

55,319

63,266

^[1]

Revenues from External Customers and Long-Lived Assets [Line Items]

14,753

8,604

6,404

Revenues from External Customers and Long-Lived Assets [Line Items]

10,190

11,447

^[1]

Americas [Member]

233,806

194,630

149,083

Revenues from External Customers and Long-Lived Assets [Line Items]

65,509

74,713

^[1]

Germany [Member]

50,102

45,664

43,751

Revenues from External Customers and Long-Lived Assets [Line Items]

3,405

4,305

^[1]

France [Member]

17,210

16,154

18,128

Other Europe, Middle East and Africa Countries [Member]

1,224

1,583

^[1]

Revenues from External Customers and Long-Lived Assets [Line Items]

49,312

42,846

40,050

Europe Middle East And Africa [Member]

11,316

4,729

^[1]

Revenues from External Customers and Long-Lived Assets [Line Items]

116,624

104,664

101,929

Revenues from External Customers and Long-Lived Assets [Line Items]

15,945

10,617

^[1]

Japan [Member]

37,757

35,478

33,686

Other Asia Pacific Countries [Member]

2,036

2,045

^[1]

Revenues from External Customers and Long-Lived Assets [Line Items]

70,728

61,607

48,635

Revenues from External Customers and Long-Lived Assets [Line Items]

8,941

2,957

^[1]

Asia Pacific [Member]

108,485

97,085

$ 82,321

Revenue From Contract With Customer [Abstract]

$ 10,977

$ 5,002

^[1]

[1]	Includes property and equipment, net and definite-lived intangible assets, net.

Retirement Benefits - Schedule of Estimated Future Benefit Payments (Detail) $ in Thousands	Dec. 31, 2019 USD ($)
Defined Benefit Plan Estimated Future Benefit Payments [Abstract]
December 31, 2020	$ 617
December 31, 2021	292
December 31, 2022	347
December 31, 2023	519
December 31, 2024	431
Next five years	$ 2,991

Schedule II - Valuation and Qualifying Accounts (Detail) - Allowance for Doubtful Accounts [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Valuation And Qualifying Accounts Disclosure [Line Items]
Balance at beginning of year	$ 1,150	$ 798	$ 565
Additions	671	394	610
Deductions	(406)	(42)	(377)
Balance at end of year	$ 1,415	$ 1,150	$ 798

Stock-based Compensation - Additional Information (Detail) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended	12 Months Ended
	Oct. 31, 2019 shares	Sep. 30, 2017 USD ($)	Dec. 31, 2019 USD ($) Installment $ / shares shares	Dec. 31, 2018 USD ($) $ / shares shares	Dec. 31, 2017 USD ($)	Sep. 27, 2017 shares	Dec. 31, 2012 shares	Dec. 31, 2001 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Business combination, estimated post combination expense		$ 2,000
Other accrued expenses and current liabilities			$ 28,603	$ 27,039
Stock Purchase Agreement [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense			700
Business combination, estimated post combination expense			$ 8,700
Weighted average remaining service period			2 years 9 months 18 days
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total requisite service period of awards			4 years
Business combination, estimated post combination expense			$ 3,400
Weighted average remaining service period			7 months 6 days
Other accrued expenses and current liabilities			$ 500	$ 600
Class A Common Stock [Member] \| Polliwog Co. Ltd. [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Business acquisition, shares issued \| shares	256,594
Business acquisition, equity interest issued or issuable, description	Stock Purchase Agreement, 256,594 shares of the Company’s Class A Common Stock will be issued to existing employees, subject to continuing employment. The shares will be issued on the one-, two- and three-year anniversaries of the closing
Class A Common Stock [Member] \| Polliwog Co. Ltd. [Member] \| Stock Purchase Agreement [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Business acquisition, shares issued \| shares	199,360
Business acquisition, equity interest issued or issuable, description	SPA Stock Consideration will be issuable in installments of 88,323 shares on the first anniversary of the closing and 91,908 shares on the second and third year anniversaries of the closing
NSO Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options, outstanding \| shares			3,557,436	4,337,856
Exercise price stock options outstanding \| $ / shares			$ 0.000025	$ 0.000025
Contractual term			35 years
Intrinsic value of options exercised			$ 28,800	$ 68,400	$ 400
ISO Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options, outstanding \| shares			103,000	532,220
Exercise price stock options outstanding \| $ / shares				$ 0.65
Contractual term			10 years
Intrinsic value of options exercised			$ 14,400	$ 5,200	25,600
ISO Plan [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options vesting period			2 years
ISO Plan [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options vesting period			3 years
ISO Plan [Member] \| Class A Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized \| shares								11,153,872
2001 ISO and NQSO Plan [Member] \| Liability for Class A Redeemable Common Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Financial liabilities					66,500
2012 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options, outstanding \| shares			1,183,817	1,541,165
Exercise price stock options outstanding \| $ / shares			$ 4.23	$ 4.12
Contractual term			10 years
Intrinsic value of options exercised			$ 11,200
Total requisite service period of awards			4 years
Compensation expense			$ 400	$ 600	$ 700
Compensation cost related to nonvested awards not yet recognized			$ 400
Weighted average period of recognition			1 year 1 month 6 days
2012 Plan [Member] \| Class A Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized \| shares							5,200,000
2017 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options, outstanding \| shares			20,000	0
Exercise price stock options outstanding \| $ / shares			$ 38.11
2017 Plan [Member] \| Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost related to nonvested awards not yet recognized			$ 22,900
Weighted average period of recognition			3 years 3 months 18 days
Weighted average grant date fair value of RSUs \| $ / shares			$ 37.23
Number of vesting equal annual installments \| Installment			4
Fair value of RSUs vested			$ 2,200
2017 Plan [Member] \| Class A Common Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for issuance \| shares						8,104,971

Stock-based Compensation - Summary of Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 8,528	$ 3,339	$ 47,281
Cost of Revenue - Software [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	1,069	31	350
Research and development [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	2,917	740	12,540
Sales and marketing [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	2,250	910	7,693
General and administrative [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 2,292	$ 1,658	$ 26,698

Revenue from Contracts with Customers

12 Months Ended

Dec. 31, 2019

Revenue from Contracts with Customers

3. Revenue from contracts with customers

Revenue recognition

Software revenue

Revenue is derived principally from the licensing of software products and from related maintenance contracts. The Company enters into contracts that include combinations of products, maintenance and services, which are accounted for as separate performance obligations with differing revenue recognition patterns.

Revenue from term-based software licenses is classified as software revenue. Term-based licenses are sold only as a bundled arrangement that includes the rights to a term software license and post-contract customer support (PCS), which includes unspecified technical enhancements and customer support. Maximizing the use of observable inputs, the Company determined that a majority of the estimated standalone selling prices of the term-based license is attributable to the term license and a minority is attributable to the PCS. The license component is classified as software revenue and recognized as revenue upon the later of delivery of the licensed product or the beginning of the license period. PCS is classified as software revenue and is recognized ratably over the term of the contract, as the Company provides the PCS benefit over time as a stand ready to perform obligation.

In addition to term-based software licenses, the Company sells perpetual licenses. Software revenue is recognized upon the later of delivery of the licensed product or the beginning of the license period. Typically, the Company’s perpetual licenses are sold with PCS. The Company allocates value in bundled perpetual and PCS arrangements based on the value relationship between the software license and maintenance. Revenue from PCS is classified as software revenue and is recognized ratably over the term of the contract, as the Company satisfies the PCS performance obligation over time as a stand ready to perform obligation.

Revenue from training, consulting and other services is recognized as the services are performed. For contracts in which the service

consists of a single performance obligation, such as providing a training class to a customer, the Company recognizes revenue upon completion of the performance obligation. For service contracts that are longer in duration and often include multiple performance obligations (for example, point-in-time training and consulting), the Company measures the progress toward completion of the obligations and recognizes revenue accordingly. In measuring progress towards the completion of performance obligations, the Company typically utilizes output-based estimates for services with fixed fee arrangements, and estimates output based on the total tasks completed as compared to the total tasks required for each contract. Input-based estimates are utilized for services that involve general consultations with contractual billing arrangements based on time and materials, utilizing direct labor as the input measure.

The Company also executes arrangements through indirect channel partners in which the channel partners are authorized to market and distribute the Company's software products to end users of the Company's products and services in specified territories. In sales facilitated by channel partners, the channel partner bears the risk of collection from the end-user customer. The Company recognizes revenue from transactions with channel partners when the channel partner submits a purchase commitment, collectability from the channel partner is probable, and the performance obligation is met, at a point in time or over time as appropriate, provided that all other revenue recognition criteria are satisfied. Revenue from channel partner transactions is the amount remitted to the Company by the channel partners. This amount includes a fee for PCS that is compensation for providing technical enhancements and the second level of technical support to the end user, which is recognized over the period that PCS is to be provided. The Company does not offer right of return, product rotation, or price protection to any of its channel partners.

Non-income related taxes collected from customers and remitted to governmental authorities are recorded on the consolidated balance sheet as Accounts receivable, net and Other accrued expenses and current liabilities. These amounts are reported on a net basis in the Consolidated statements of operations and do not impact reported revenues or expenses. Certain hardware revenue is included within software revenue and is recognized when all revenue recognition criteria stated above are met, which is generally when the products are delivered to end customers.

Significant judgments

Software revenue

The Company’s contracts with customers typically include promises to transfer licenses and services to a customer. Judgment is required to determine if the promises are separate performance obligations within the context of the arrangement, and if so, the allocation of the transaction price to each performance obligation. The Company’s determination of standalone selling price for performance obligations is based on the midpoint of the range of historical observable prices for goods and services sold separately. In addition, the Company estimates the standalone selling price for certain performance obligations where observable prices are not directly available or a significant portion of historical prices are not within the range. The Company estimates standalone selling price at contract inception considering all information that is reasonably available and is based on the amount of consideration for which the Company expects to be entitled in exchange for transferring the promised good or service to the customer. The corresponding revenues are recognized as the related performance obligations are satisfied.

The Company’s contracts do not include a significant financing component requiring adjustment to the transaction price. Payment terms vary by contract type, however, arrangements typically stipulate a requirement for the customer to pay within 30 to 60 days.

The Company rarely enters into agreements to modify previously executed contracts, which constitute contract modifications. The Company assess’ each of these contract modifications to determine (i) if the additional products and services are distinct from the products and services in the original arrangement; and (ii) if the amount of consideration expected for the added products and services reflects the stand-alone selling price of those products and services, as adjusted for contract-specific circumstances. A contract modification meeting both criteria is accounted for as a separate contract. A contract modification not meeting both criteria is considered a change to the original contract and is accounted for on either (i) a prospective basis as a termination of the existing contract and the creation of a new contract; or (ii) a cumulative catch-up basis. Generally, the Company’s contract modifications meet both criteria and are accounted for as a separate contract, as adjusted for contract-specific circumstances.

Software related services revenue

Consulting services from product design and development projects are considered distinct performance obligations and are provided to customers on a time-and-materials (“T&M”) or fixed-price basis. Altair recognizes software services revenue for T&M contracts based upon hours worked and contractually agreed-upon hourly rates using the input method. Revenue from fixed-price engagements is recognized using the output method based on the ratio of costs incurred, to the total estimated project costs.

Client engineering services and Other revenue

Client engineering services revenue are derived from professional services for staffing primarily representing engineers and data scientists located at a customer site. These professional services are considered distinct performance obligations and are provided to customers on a T&M basis. The Company recognizes this revenue for T&M contracts based upon hours worked and contractually agreed-upon hourly rates using the input method. No significant judgments were made for revenue recognition related to businesses included within Other revenue.

Adoption of ASC 606, Revenue from Contracts with Customers

The Company adopted ASC 606 on January 1, 2018, using the modified retrospective approach for all contracts not completed as of the date of adoption. Results for reporting periods beginning on or after January 1, 2018, are presented under ASC 606, while prior period amounts are not adjusted and continue to be reported in accordance with ASC 605, and other industry specific guidance. The adoption of ASC 606 represents a change in accounting principle that will more closely align revenue recognition with the transfer of promised goods or services to a customer in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. ASC 606 requires an entity to evaluate revenue recognition by identifying a contract with a customer, identifying the performance obligations in the contract, determining the transaction price, allocating the transaction price to the performance obligations in the contract, and recognizing revenue when (or as) the entity satisfies a performance obligation. Topic 606 also includes Subtopic 340-40 which provides accounting guidance for incremental costs of obtaining a contract with a customer. The Company refers to Topic 606 and Subtopic 340-40 collectively as “ASC 606.” The Company elected not to apply any of the practical expedients which were allowed in the application of this new guidance.

The Company recorded a decrease to accumulated deficit of $84.6 million, or $77.7 million net of tax, on January 1, 2018, due to the cumulative effect of the ASC 606 adoption, with the impact primarily derived from revenue related to software licenses recognized at a point in time under ASC 606 that were historically recognized over time. There was no impact on Client Engineering Services or Other revenue upon the adoption of ASC 606.

The following table presents the effect of the adoption of ASC 606 on the consolidated statement of operations (in thousands):

	Year Ended December 31, 2018
	Prior to adoption of ASC 606		Adjustments for ASC 606			As Reported
Revenue
Licenses	$	195,847	$	11,317		$	207,164
Gross profit	$	269,089	$	11,317		$	280,406
Operating expenses
Sales and marketing	$	80,613	$	(336	)	$	80,277
Total operating expenses	$	256,098	$	(336	)	$	255,762
Operating income	$	12,991	$	11,653		$	24,644
Income before income taxes	$	15,371	$	11,653		$	27,024
Income tax expense	$	10,829	$	660		$	11,489
Net income	$	4,542	$	10,993		$	15,535
Income per share:
Basic	$	0.07	$	0.16		$	0.23
Diluted	$	0.06	$	0.15		$	0.21

The increase to software revenue was primarily due to the upfront recognition of license revenue, which would have been recognized ratably over the contract under prior guidance. The decrease in sales and marketing expense was due to the capitalization of costs to obtain a contract that were expensed as incurred under prior guidance. The increase to tax expense was due to the tax impact of the increase in operating income.

The Company recorded $82.9 million of deferred revenue to accumulated deficit upon the adoption of ASC 606 on January 1, 2018. The adoption of ASC 606 accelerated the recognition of revenues compared to ASC 605. Under ASC 605, the Company did not have vendor-specific objective evidence (“VSOE”) of fair value for post-contract customer support (“PCS”) sold along with software products licenses; therefore, revenues for the software products licenses (including perpetual licenses), PCS and professional services, if applicable, were considered to be one accounting unit and, once all services have commenced, were recognized ratably over the remaining period of the arrangement (the longer of the contractual service term or PCS term). Under ASC 606, the concept of assessing VSOE has been eliminated and the Company determined standalone selling price and allocated transaction price associated with each performance obligation within an arrangement. As a result, the pattern of software license revenue recognition has changed under ASC

606. Software license revenue was typically recognized ratably over the term of the contract under the previous guidance; however, a majority of the contract is recognized upon the later of delivery of the licensed product or the beginning of the license period under ASC 606.

The adoption of ASC 606 had no impact on the Company’s cash flows from operations.

Disaggregation of revenue

The Company disaggregates its software revenue by type of performance obligation and timing of revenue recognition as follows (in thousands):

	Year Ended December 31,
	2019 (ASC 606)		2018 (ASC 606)		2017 (ASC 605)⁽¹⁾
Software revenue:
Term licenses	$	201,881	$	168,909
Perpetual licenses		42,440		38,255
Maintenance		103,699		86,150
Professional services and other		18,682		11,047
Total software revenue	$	366,702	$	304,361	$	244,817

(1)	As noted above, prior period amounts have not been adjusted under the modified retrospective approach of ASC 606.

Under ASC 606, the Company derived approximately 10% of its total revenue through indirect sales channels for the year ended December 31, 2019 and 2018.

For the year ended December 31, 2019, software related services revenue, client engineering services revenue, and other revenue were categorized based on the nature and timing of revenue and cash flows.

Costs to obtain a contract

The Company pays commissions for new software product and PCS sales as well as for renewals of existing software and PCS contracts. Commissions paid to obtain renewal contracts are not commensurate with the commissions paid for new product sales and therefore, a portion of the commissions paid for new contracts relate to future renewals.

The Company accounts for new product sales commissions using a portfolio approach and allocates the cost of commissions in proportion to the allocation of transaction price of license and PCS performance obligations. Commissions allocated to the license and license renewal components are expensed at the time the license revenue is recognized. Commissions allocated to PCS are capitalized and amortized on a straight-line basis over a period of four years, reflecting the Company’s estimate of the expected period that it will benefit from those commissions. As of December 31, 2019 and 2018, respectively, capitalized costs to obtain a contract were $2.3 million and $2.0 million recorded in Prepaid and other current assets and $0.8 million and $0.2 million recorded in Other long-term assets. Amortization expense was $4.5 million and $0.3 million for the years ended December 31, 2019 and 2018, respectively, and were included in sales and marketing expense in the Company’s consolidated statement of operations.

Contract assets

At December 31, 2019 and 2018, contract assets were $4.5 million and $3.7 million, respectively, recorded in accounts receivable, and $2.7 million and $2.7 million, respectively, recorded in prepaid expenses and other current assets.

Deferred revenue

Deferred revenue consists of billings made or payments received in advance of revenue recognition from software license, PCS and professional services agreements. The timing of revenue recognition may differ from the timing of billings to customers. Payment terms vary by the type and location of customer and the products or services offered. The term between invoicing and when payment is due is not significant. The Company generally invoices its customers annually for the forthcoming year of software licenses, and more frequently for other products and services. Accordingly, the Company’s deferred revenue balance does not include revenue for future years of multiple year non-cancellable contracts that have not yet been billed. At December 31, 2019, the Company expects to recognize its remaining contractual obligations over the next 12 – 24 months. Approximately $57.8 million of revenue was recognized during 2019 was included in the deferred revenue balances at the beginning of the year.

Stock-based Compensation - Summary of Stock Option Activity under NSO Plan (Detail) - NSO Plan [Member] - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Number of options, Outstanding, Beginning Balance	4,337,856
Number of options, Exercised	(780,420)
Number of options, Forfeited	0
Number of options, Outstanding and exercisable, Ending Balance	3,557,436
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Weighted average exercise price per share, Outstanding, Beginning Balance	$ 0.000025
Weighted average exercise price per share, Exercised	0.000025
Weighted average exercise price per share, Forfeited	0
Weighted average exercise price per share, Outstanding and exercisable, Ending Balance	$ 0.000025
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted average remaining contractual term (years), Outstanding		18 years
Weighted average remaining contractual term (years), Outstanding and exercisable	17 years
Aggregate intrinsic value, Outstanding		$ 119.6
Aggregate intrinsic value, Outstanding and exercisable	$ 127.8

Leases - Schedule of Maturities of Operating Lease Liabilities (Detail) $ in Thousands	Dec. 31, 2019 USD ($)
Leases [Abstract]
2020	$ 10,444
2021	8,177
2022	5,768
2023	3,684
2024	1,730
Thereafter	3,055
Total lease payments	32,858
Less: imputed interest	3,543
Total operating lease liabilities	$ 29,315

Financial Instruments

12 Months Ended

Dec. 31, 2019

Investments All Other Investments [Abstract]

Financial Instruments

11. Financial instruments

The Company is exposed to certain financial market risks related to its ongoing business operations. The primary risks the Company can manage through derivative financial instruments and hedging activities are foreign currency exchange rate risk and interest rate risk. Derivative financial instruments and hedging activities can be utilized to protect the Company’s cash flow from adverse movements in foreign currency exchange rates and to manage interest costs. Although the Company is exposed to credit loss in the event of nonperformance by the counterparty to the derivative financial instruments, the Company attempts to limit this exposure by entering into agreements directly with major financial institutions that meet the Company’s credit standards and that are expected to fully satisfy their obligations under the contracts.

Interest rate swaps

Interest rate exposures are reviewed periodically, and the Company may enter into interest rate swap agreements to manage its exposure. The Company’s exposure to interest rate risk arises primarily from changes in the LIBOR rate. The Company will hold these derivatives for economic purposes but does not designate these derivatives to obtain hedge accounting treatment. As such, gains or losses on these contracts (including contracts that do not qualify for hedge accounting under ASC 815), are reported in earnings immediately as Other (income) expense, net. These contracts limit exposure to changes in interest payments associated with variable rate debt. However, as the change in the fair value of the interest rate swaps is impacted by both realized and unrealized gains and losses on the contracts, the amount recognized in earnings may not offset the changes in the variability of interest expense during a given period.

As of December 31, 2019, the Company had no interest rate swaps outstanding. As of December 31, 2018, the Company had an interest rate swap outstanding with a $4.5 million notional value which matured on December 23, 2019.

Foreign currency derivatives

The Company sells its products (and incurs costs) in countries throughout the world. As a result, it is exposed to fluctuations in foreign currency exchange rates. Foreign currency exposures are reviewed on a periodic basis and any natural offsets are considered prior to entering into a derivative financial instrument. The Company could enter into foreign exchange contracts to hedge portions of its foreign currency denominated forecasted revenues, purchases and the subsequent cash flows after considering natural offsets within the consolidated group. The Company will hold these derivatives for economic purposes but does not designate these derivatives to obtain hedge accounting treatment. As such, gains or losses on these contracts (including contracts that do not qualify for hedge accounting under ASC 815), are reported in earnings immediately and are substantially offset by the effect of the revaluation of the underlying foreign currency denominated transactions. There were no foreign exchange contracts outstanding at December 31, 2019 or 2018.

Credit-risk-related contingent features

The Company has entered into International Swaps and Derivatives Association (“ISDA”) agreements with its significant derivative counterparty. These agreements provide bilateral netting and offsetting of accounts that are in a liability position with those that are in an asset position. These agreements do not require the Company to maintain a minimum credit rating in order to be in compliance and do not contain any margin call provisions or collateral requirements that could be triggered by derivative instruments in a net liability position. The Company did not have any outstanding derivative instruments at December 31, 2019.

Stock-based Compensation - Summary of Restricted Stock Units Awarded (Detail) - 2017 Plan [Member] - Restricted Stock Units (RSUs) [Member]	12 Months Ended
	Dec. 31, 2019 shares
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Number of RSUs, Outstanding Beginning Balance	206,061
Number of RSUs, Granted	694,690
Number of RSUs, Vested	(60,388)
Number of RSUs, Forfeited	(59,062)
Number of RSUs, Outstanding Ending Balance	781,301

Acquisitions and Disposals

12 Months Ended

Dec. 31, 2019

Business Combinations [Abstract]

Acquisitions and Disposals

4. Acquisitions and disposals

Polliwog

In October 2019, the Company entered into a stock purchase agreement (the “Stock Purchase Agreement”) and simultaneously acquired 97% of the outstanding capital stock of Polliwog Co. Ltd. (“Polliwog”), a software company based near Seoul, Korea. The Company will pay an additional $0.3 million in cash and issue an additional 14,213 shares of its Class A Common Stock in October 2022, subject to a Second Stock Purchase Agreement, to complete the purchase of the remaining three percent of Polliwog’s outstanding capital stock. Polliwog is a supplier of Electronic Design Automation software to the global electronics industry, which will expand Altair’s ability to provide software for system-level design decisions. The Company believes Polliwog’s printed circuit board solvers and verification tools will integrate well with Altair’s existing HyperWorks software solutions.

The closing consideration per the Stock Purchase Agreement of $19.3 million consisted of cash in the amount of $10.7 million, subject to a customary working capital adjustment, $2.2 million of cash paid on the day of closing to settle all of Polliwog’s outstanding debt and an aggregate of 199,360 shares of the Company’s Class A Common Stock, par value $0.0001 per share (the “SPA Stock Consideration”), 183,815 shares of which were issued at closing (which occurred concurrently with the execution of the Stock Purchase Agreement) and are subject to customary securities law restrictions on transferability for the first six months after the closing. The remaining 15,545 shares of the SPA Stock Consideration will be issuable in installments of 88,323 shares on the first anniversary of the closing and 91,908 shares on the second and third year anniversaries of the closing, subject to potential reduction in certain circumstances and subject to customary securities law restrictions on transferability. In addition, per the Stock Purchase Agreement, 256,594 shares of Class A Common Stock will be issued subject to the continuing employment of certain key employees and are not reflected in aggregate consideration but will be recognized as stock-based compensation over the employment period. The closing consideration per the Second Stock Purchase Agreement of $0.8 million consists of $0.3 million in cash and an additional 14,213 shares of the Company’s Class A Common Stock to be issued in October 2022.

The purchase price was allocated to assets and liabilities of Polliwog based on the fair value of the assets acquired and liabilities assumed. The allocation included $2.9 million to land and building, $0.5 million to customer relationships, $0.5 million to tradenames, $0.4 million to developed technology, and $15.4 million to goodwill, which is not tax deductible. The financial results of Polliwog have been included in the consolidated financial statements since the acquisition date.

The allocation of fair value of purchase consideration is subject to change within the measurement period (up to one year from the acquisition date). The primary areas that remain preliminary relate to the fair value of intangible assets acquired, certain tangible assets and liabilities acquired, income taxes and residual goodwill.

DEM Solutions Limited

In November 2019, the Company entered into a stock purchase agreement and simultaneously acquired 100% of the outstanding capital stock of DEM Solutions Limited (“DEM Solutions”), a company that provides market-leading Discrete Element Method software for bulk material simulation, based in Edinburgh, UK, for aggregate consideration of $13.1 million. The acquisition of DEM Solutions enables Altair to provide new technology and solutions to customers in the agricultural, mining, material handling, construction and heavy machinery, chemical and pharmaceutical industries.

The purchase price was allocated to assets and liabilities of DEM Solutions based on the fair value of the assets acquired and liabilities assumed. The purchase price fair value was primarily allocated to $3.7 million to developed technology, $3.1 million to customer relationships, $0.6 million to tradenames and $5.6 million to goodwill, which is not tax deductible. The financial results of DEM Solutions have been included in the consolidated financial statements since the acquisition date.

Datawatch Corporation

On November 5, 2018, the Company entered into an Agreement and Plan of Merger (“Merger Agreement”) with Datawatch Corporation, a Delaware corporation (“Datawatch”), and Dallas Merger Sub, Inc., a Delaware corporation (“Purchaser”) and a wholly owned subsidiary of the Company.

Pursuant to the Merger Agreement, the Purchaser commenced a tender offer to purchase all of the issued and outstanding shares of Datawatch common stock, (the “Shares”) at a purchase price of $13.10 per share, net to seller in cash, without interest and less any applicable withholding taxes (the “Offer”).

On December 13, 2018, the Company accepted and paid for all Shares that were validly tendered and completed the acquisition of Datawatch through the merger of Purchaser with and into Datawatch, with Datawatch surviving as a wholly owned subsidiary of the Company.

Altair completed the acquisition of Datawatch for consideration of approximately $183.4 million which consisted of consideration paid to former holders of common stock of Datawatch at $13.10 a share, or $168.2 million and approximately $6.7 million to former holders of outstanding Datawatch equity awards. In addition, Altair paid $8.0 million on the day of closing to settle all of Datawatch’s outstanding debt and incurred a liability of approximately $0.5 million payable to former holders of certain unvested Datawatch equity awards for which service had been rendered at the acquisition date. Altair financed the acquisition with cash on hand and a drawdown from its existing credit facility.

In connection with the acquisition of Datawatch, the Company incurred $10.4 million of transaction related costs, which consisted primarily of fees paid to investment bankers’ and employee severance, which were recorded to general and administrative, sales and marketing, and research and development expenses in the consolidated statement of operations for the year ended December 31, 2018.

The financial results of Datawatch have been included in the consolidated financial statements since the acquisition date.

The acquisition of Datawatch has been accounted for as a business combination, under the acquisition method of accounting, which results in acquired assets and assumed liabilities being measured at their estimated fair values as of December 13, 2018, the acquisition date. As of the acquisition date, goodwill is measured as the excess of consideration transferred, which is also generally measured at fair value of the net acquisition date fair values of the assets acquired and liabilities assumed. The allocation of fair value of purchase consideration was finalized in 2019.

The following table summarizes the purchase consideration transferred to acquire Datawatch and the amounts of identified assets acquired and liabilities assumed at the acquisition date (in thousands):

Fair value of consideration transferred	$	183,427
Recognized amounts of identifiable assets acquired and liabilities assumed:
Cash	$	8,278
Accounts receivable		10,384
Other assets		2,522
Property and equipment		980
Trade names		7,400
Developed technology (6-year life)		22,600
Customer relationships (10-year life)		16,700
Accounts payable and other liabilities		(5,041	)
Deferred revenue		(3,649	)
Other long-term liabilities		(8,340	)
Total net identifiable assets acquired and liabilities assumed		51,834
Goodwill ⁽¹⁾	$	131,593

(1)	Goodwill is primarily attributable to market synergies expected to arise after the acquisition and approximately $0.8 million is deductible for tax purposes. All goodwill is recorded in the Software segment.

The consummation of the merger resulted in a change in control which accelerated vesting for certain restricted stock units (“RSUs”) of Datawatch. These RSUs were converted into the right to receive merger consideration in the amount of $6.7 million, which is included in total consideration transferred.

The consummation of the merger also modified certain Datawatch RSUs without change in control provisions. These RSUs were modified such that the holder has the right to receive cash payments upon vesting at $13.10 per share in the amount of $3.9 million, of which $0.5 million was allocated to pre-combination expense and consideration transferred as it relates to service prior to the acquisition date. The remaining $3.4 million was preliminarily allocated to future services and will be expensed over the remaining service periods on a straight-line basis.

The excess of preliminary purchase consideration over the fair value of net tangible and identifiable intangible assets acquired was recorded as goodwill.

SIMSOLID Corporation

In October 2018, the Company acquired all of the outstanding capital stock of SIMSOLID Corporation, a Canadian corporation, for aggregate consideration of $22.1 million. The allocation of fair value of purchase consideration was finalized in the first quarter of 2019, and there were no changes to the fair value of assets acquired and liabilities assumed, as previously reported.

Other business acquisitions

During the years ended December 31, 2019 and 2018, the Company completed other business acquisitions that were individually and in the aggregate insignificant. The Company has accounted for all of its acquisitions using the acquisition method. The operating results of each acquisition have been included in the consolidated financial statements since the respective dates of acquisition.

For significant acquisitions the Company engaged a third-party valuation firm to assist the Company in valuing certain assets and liabilities acquired.

WEYV

In July 2019, the Company decided to sunset operations of its WEYV business, a consumer music and content service. The Company concluded that this decision was not a strategic shift that has or will have a major effect on its operations and financial results, and therefore did not meet the accounting criteria to be classified as a discontinued operation.

The operations of WEYV terminated in the third quarter of 2019. The loss on disposal was not material, and is included in other operating income in the consolidated statement of operations. WEYV had a loss before income tax of $3.0 million and $4.2 million for the years ended December 31, 2019 and 2018, respectively. The WEYV business is reported in All Other within the Company’s segment information in Note 19.

Leases - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Lessee Lease Description [Line Items]
Rent cost for operating leases	$ 11,800	$ 11,000	$ 9,900
Finance lease obligations, total	$ 1,174
Adoption of Topic 842 [Member]
Lessee Lease Description [Line Items]
Finance lease obligations, total		$ 800
Minimum [Member]
Lessee Lease Description [Line Items]
Leases, remaining lease term	0 years
Maximum [Member]
Lessee Lease Description [Line Items]
Leases, remaining lease term	7 years 10 months 24 days
Operating leases, options to extend lease term	6 years
Leases, options to terminate leases	4 years

Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2013
Software and Other [Member]
Loss Contingencies [Line Items]
Royalty fees	$ 10.6	$ 9.7	$ 9.3
Datawatch Corporation [Member] \| Panopticon AB [Member] \| Swedish Tax Authorities [Member]
Loss Contingencies [Line Items]
Tax assessment, penalties and interest amount related to acquisition				$ 6.5

Summary of Significant Accounting Policies - Schedule of Allowance for Doubtful Accounts (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accounts Notes Loans And Financing Receivable Gross Allowance And Net [Abstract]
Balance, beginning of year	$ (1,150)	$ (798)	$ (565)
Provision charged to expense	(671)	(394)	(610)
Write-offs, net of recoveries	413	3	414
Effects of foreign currency translation	(7)	39	(37)
Balance, end of year	$ (1,415)	$ (1,150)	$ (798)

Other Liabilities (Tables)

12 Months Ended

Dec. 31, 2019

Other Liabilities Disclosure [Abstract]

Summary of Other Accrued Expenses and Current Liabilities

The following table provides the details of other accrued expenses and current liabilities (in thousands):

	December 31,
	2019		2018
Income taxes payable	$	6,008	$	3,932
Accrued VAT		5,312		4,536
Accrued professional fees		2,581		3,165
Accrued royalties		2,314		2,613
Defined contribution plan liabilities		1,593		1,376
Obligations for acquisition of businesses		1,362		1,218
Non-income tax liabilities		1,253		853
Billings in excess of cost		879		1,504
Other current liabilities		7,301		7,842
Total	$	28,603	$	27,039

Summary of Other Long-term Liabilities

The following table provides the details of other long-term liabilities (in thousands):

	December 31,
	2019		2018
Pension and other post retirement liabilities	$	10,379	$	9,111
Deferred tax liabilities		6,275		5,339
Other liabilities		10,018		11,306
Total	$	26,672	$	25,756

Income Taxes - Reconciliation of Beginning and Ending Amounts of Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Unrecognized tax benefits-January 1	$ 17,097	$ 6,157	$ 5,604
Additions for tax positions of current period	(203)
Additions for tax positions of current period		234	634
Additions for tax positions of prior periods	642	10,866
Reductions for tax positions of prior periods	(1,834)	(100)	(81)
Reductions due to statute of limitations	(162)	(60)
Unrecognized tax benefits—December 31	$ 15,540	$ 17,097	$ 6,157

Acquisitions and Disposals (Tables)

12 Months Ended

Dec. 31, 2019

Business Combinations [Abstract]

Summary of Amounts of Identified Assets Acquired and Liabilities Assumed at the Acquisition Date

Fair value of consideration transferred	$	183,427
Recognized amounts of identifiable assets acquired and liabilities assumed:
Cash	$	8,278
Accounts receivable		10,384
Other assets		2,522
Property and equipment		980
Trade names		7,400
Developed technology (6-year life)		22,600
Customer relationships (10-year life)		16,700
Accounts payable and other liabilities		(5,041	)
Deferred revenue		(3,649	)
Other long-term liabilities		(8,340	)
Total net identifiable assets acquired and liabilities assumed		51,834
Goodwill ⁽¹⁾	$	131,593

(1)	Goodwill is primarily attributable to market synergies expected to arise after the acquisition and approximately $0.8 million is deductible for tax purposes. All goodwill is recorded in the Software segment.

(Loss) Income Per Share - Additional Information (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2019	Jun. 30, 2019
Earnings Per Share Basic [Line Items]
Anti-dilutive shares excluded from computation of (loss) income per share	5,700,000	0	10,200,000
Class A Common Stock [Member] \| Convertible Senior Notes Due in 2024 [Member]
Earnings Per Share Basic [Line Items]
Debt instrument convertible initial conversion price per share of common stock				$ 46.50	$ 46.50

Fair Value Measurements - Additional Information (Detail) $ in Millions	Dec. 31, 2019 USD ($)
Fair Value Disclosures [Abstract]
Fair value of convertible notes	$ 236.1

Income Taxes - Operating Loss and Tax Credit Carryforwards (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($)
Operating Loss and Tax Credit Carryforward [Line Items]
Foreign loss carryforwards, expiration year	Indefinite
U.S. foreign tax credits, expiration year	2027
U.S. foreign tax credits	$ 12,471
Total operating loss and tax credit carryforwards	77,726
Foreign Tax Authority [Member]
Operating Loss and Tax Credit Carryforward [Line Items]
Foreign loss carryforwards	$ 9,182
General Business Tax Credit Carryforward [Member]
Operating Loss and Tax Credit Carryforward [Line Items]
U.S. general business credits and loss carryforwards, expiration year	2020-Indefinite
Foreign loss carryforwards	$ 56,073

Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 13, 2018
Deferred tax assets:
Deferred revenue	$ 11,408	$ 1,962
Net operating loss carryforwards	38,745	38,179
Tax credit carryforwards	38,981	31,600
Stock-based compensation	6,480	6,858
Capitalized research and development	7,162	8,266
Lease obligation	7,579
Employee benefits	5,189	4,756
Other	1,968	1,999
Total gross deferred tax assets	117,512	93,620
Less: valuation allowances	(84,356)	(78,155)
Net deferred tax assets	33,156	15,465
Deferred tax liabilities:
Property and equipment and intangibles	13,588	13,966
Deferred tax on investment in subsidiary	474	329
Lease right of use asset	7,247
Convertible debt, net of issuance costs	10,899
Other	1,432	1,154
Total deferred tax liabilities	33,640	15,449
Total net deferred tax (liabilities) assets	$ (484)
Total net deferred tax (liabilities) assets		$ 16

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2019

Components of Income (Loss) Before Income Taxes

The components of income (loss) before income taxes are as follows (in thousands):

	Year ended December 31,
	2019			2018		2017
U.S.	$	(14,732	)	$	4,228	$	(49,761	)
Non-U.S.		18,120			22,796		13,350
	$	3,388		$	27,024	$	(36,411	)

Schedule of Significant Components of Income Tax Expense

The significant components of the income tax expense are as follows (in thousands):

	Year ended December 31,
	2019			2018			2017
Current
U.S. Federal	$	—		$	2		$	—
Non-U.S.		11,434			12,629			10,290
U.S. State and Local		446			(16	)		135
Total current		11,880			12,615			10,425
Deferred
U.S. Federal		193			1,714			54,130
Non-U.S.		(1,143	)		(2,823	)		1,228
U.S. State and Local		-			(17	)		(253	)
Total deferred		(950	)		(1,126	)		55,105
Income tax expense	$	10,930		$	11,489		$	65,530

Reconciliation of Income Taxes Calculated at U.S. Federal Statutory Income Tax Rate

The reconciliation of income taxes calculated at the U.S. Federal statutory income tax rate to income tax expense is as follows (in thousands):

	Year ended December 31,
	2019			2018			2017
U.S. federal statutory rate		21	%		21	%		35	%
Income taxes at U.S. federal statutory rate	$	711		$	5,675		$	(12,744	)
Foreign income taxes at rates other than the federal statutory rate		1,247			2,179			373
U.S. state and local income taxes, net of U.S. federal tax benefit		(6,836	)		(3,453	)		(155	)
U.S. Tax Cut and Jobs Act: transition tax, net of foreign tax credits		—			—			4,187
U.S. effect of foreign operations		8,609			—			—
Change in valuation allowance		18,138			21,544			49,859
Foreign withholding taxes		5,975			5,103			4,181
U.S. foreign tax credit		(7,059	)		(5,648	)		(4,154	)
Research and development tax credit		(2,600	)		(2,819	)		(2,999	)
Stock-based compensation		(4,574	)		(14,964	)		10,871
Meals & entertainment		246			181			358
Other		(1,068	)		1,206			(59	)
Uncertain tax positions		(1,859	)		903			446
Acquisition costs		—			503			—
Tax law changes		—			1,079			15,366
Income tax expense	$	10,930		$	11,489		$	65,530

Schedule of Deferred Tax Assets and Liabilities

	December 31,
	2019			2018
Deferred tax assets:
Deferred revenue	$	11,408		$	1,962
Net operating loss carryforwards		38,745			38,179
Tax credit carryforwards		38,981			31,600
Stock-based compensation		6,480			6,858
Capitalized research and development		7,162			8,266
Lease obligation		7,579			—
Employee benefits		5,189			4,756
Other		1,968			1,999
Total gross deferred tax assets		117,512			93,620
Less: valuation allowances		(84,356	)		(78,155	)
Net deferred tax assets⁽¹⁾		33,156			15,465
Deferred tax liabilities:
Property and equipment and intangibles		13,588			13,966
Deferred tax on investment in subsidiary		474			329
Lease right of use asset		7,247			—
Convertible debt, net of issuance costs		10,899			—
Other		1,432			1,154
Total deferred tax liabilities		33,640			15,449
Total net deferred tax (liabilities) assets	$	(484	)	$	16

(1)	Reflects gross amount before jurisdictional netting of deferred tax assets and liabilities.

Summary of Changes to Valuation Allowance Balance

The following table summarizes the changes to the valuation allowance balance at December 31, 2019, 2018 and 2017 (in thousands):

	December 31,
	2019			2018			2017
Beginning balance	$	78,155		$	56,761		$	4,153
Additions charged to expense		18,138			21,544			49,859
Other		(11,937	)		(150	)		2,749
Ending balance	$	84,356		$	78,155		$	56,761

Summary of Operating Loss and Tax Credit Carryforwards

The following table summarizes the amount and expiration dates of operating loss and tax credit carryforwards at December 31, 2019 (in thousands):

	Expiration dates	Amounts
U.S. general business credits and loss carryforwards	2020-Indefinite	$	56,073
Foreign loss carryforwards	Indefinite		9,182
U.S. foreign tax credits	2027		12,471
Total operating loss and tax credit carryforwards		$	77,726

Reconciliation of Beginning and Ending Amounts of Unrecognized Tax Benefits

A reconciliation of the beginning and ending amounts of unrecognized tax benefits is as follows (in thousands):

	Year ended December 31,
	2019			2018			2017
Unrecognized tax benefits—January 1	$	17,097		$	6,157		$	5,604
Increase in unrecognized tax benefits as a result of:
Additions for tax positions of current period		(203	)		234			634
Additions for tax positions of prior periods		642			10,866			—
Reductions for tax positions of prior periods		(1,834	)		(100	)		(81	)
Reductions due to statute of limitations		(162	)		(60	)		—
Unrecognized tax benefits—December 31	$	15,540		$	17,097		$	6,157

Document and Entity Information - USD ($) $ in Billions	12 Months Ended
Document and Entity Information - USD ($) $ in Billions	Dec. 31, 2019	Feb. 15, 2020	Jun. 28, 2019
Document And Entity Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Trading Symbol	ALTR
Entity Registrant Name	ALTAIR ENGINEERING INC.
Entity Central Index Key	0001701732
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 1.6
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity File Number	001-38263
Entity Tax Identification Number	38-2591828
Entity Address, Address Line One	1820 East Big Beaver Road
Entity Address, City or Town	Troy
Entity Address, State or Province	MI
Entity Address, Postal Zip Code	48083
City Area Code	248
Local Phone Number	614-2400
Entity Incorporation, State or Country Code	DE
Document Annual Report	true
Document Transition Report	false
Title of 12(b) Security	Class A Common Stock $0.0001 par value per share
Security Exchange Name	NASDAQ
Documents Incorporated by Reference	Portions of the registrant’s Proxy Statement relating to the 2020 Annual Meeting of Stockholders, scheduled to be filed with the Securities and Exchange Commission within 120 days after the end of the registrant’s fiscal year ended December 31, 2019, are incorporated by reference into Part III of this Annual Report on Form 10-K.
Class A Common Stock [Member]
Document And Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		41,408,517
Class B Common Stock [Member]
Document And Entity Information [Line Items]
Entity Common Stock, Shares Outstanding		31,130,732

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2019

Immaterial Corrections of Prior Period Financial Statements

Immaterial corrections of prior period financial statements

In connection with the preparation of its financial statements for the quarter ended June 30, 2019, the Company identified and corrected certain errors that were immaterial to previously-reported consolidated financial statements. No such adjustments are necessary for the year ended December 31, 2019, nor does the Company anticipate any further adjustments based on these errors. These historical errors related primarily to i) the cumulative effective adjustment for the income tax effect of intercompany transactions resulting from the adoption of Accounting Standards Codification (“ASC”) No. 606, Revenue from Contracts with Customers (ASC 606) on January 1, 2018, and ii) income tax accounting for acquisitions. The Company evaluated the materiality of these errors both qualitatively and quantitatively in accordance with Staff Accounting Bulletin (“SAB”) No. 99, Materiality, and SAB No. 108, Considering the Effects of Prior Year Misstatements When Quantifying Misstatements in Current Year Financial Statements, and determined the effect of these corrections was not material to the previously issued financial statements. However, the effect of correcting these errors in the current period would be material to the current period financial statements. Therefore, the amounts in the previous periods have been revised to reflect the correction of these errors. These revisions do not impact amounts previously reported in the consolidated statements of operations for the three months ended March 31, 2019 and 2018, the three and six months ended June 30, 2018, the three and nine months ended September 30, 2018, or for total operating, investing, or financing activities on the consolidated statements of cash flows for any previously reported period.

The following table presents the effect of the error corrections on the Company’s consolidated balance sheet for the period indicated (in thousands):

	As of December 31, 2018
	As Reported			Adjustments			As Corrected
Deferred tax assets	$	1,373		$	3,981		$	5,354
Total assets	$	483,216		$	3,981		$	487,197
Other accrued expenses and current liabilities	$	27,565		$	(526	)	$	27,039
Total current liabilities	$	127,758		$	(526	)	$	127,232
Other long-term liabilities	$	28,153		$	(2,397	)	$	25,756
Total liabilities	$	194,082		$	(2,923	)	$	191,159
Accumulated deficit	$	(82,005	)	$	7,142		$	(74,863	)
Accumulated other comprehensive loss	$	(11,052	)	$	(238	)	$	(11,290	)
Total stockholders' equity	$	286,782		$	6,904		$	293,686
Total liabilities, mezzanine equity and stockholders' equity	$	483,216		$	3,981		$	487,197

The adjustments for amounts similar to the above were also made to the Company’s consolidated balance sheets as of March 31, 2018, June 30, 2018, September 30, 2018, and March 31, 2019, respectively. Additionally, the Company revised goodwill, total assets, and total liabilities, mezzanine equity and stockholders’ equity on the consolidated balance sheet as of December 31, 2017 and 2016, to correct these errors, resulting in a decrease of $1.6 million and $0.9 million, respectively, from the previously reported amounts. The consolidated statements of changes in stockholders’ equity (deficit) for the three month periods ended March 31, 2018 and 2019 have been corrected to reflect the adjustments described herein.

The following tables present the effect of the error corrections on the consolidated statements of operations for the periods indicated (in thousands, except per share data):

	Year Ended December 31, 2018
	As Reported		Adjustments			As Corrected
Income before income taxes	$	27,024	$	—		$	27,024
Income tax expense	$	13,309	$	(1,820	)	$	11,489
Net income	$	13,715	$	1,820		$	15,535
Net income per share attributable to common stockholders, basic	$	0.20	$	0.03		$	0.23
Net income per share attributable to common stockholders, diluted	$	0.18	$	0.03		$	0.21

	Year Ended December 31, 2017
	As Reported			Adjustments			As Corrected
Loss before income taxes	$	(36,411	)	$	—		$	(36,411	)
Income tax expense	$	62,996		$	2,534		$	65,530
Net loss	$	(99,407	)	$	(2,534	)	$	(101,941	)
Net loss per share attributable to common stockholders, basic	$	(1.89	)	$	(0.05	)	$	(1.94	)
Net loss per share attributable to common stockholders, diluted	$	(1.89	)	$	(0.05	)	$	(1.94	)

Additionally, the Company revised income tax expense, net income, and net income per share attributable to common stockholders (basic and diluted) on the consolidated statement of operations for the year ended December 31, 2016, to correct these errors, resulting in an increase of $0.2 million, a decrease of $0.2 million and a decrease of $0.01, respectively, from the previously reported amounts.

Principles of Consolidation

Principles of consolidation

The accompanying consolidated financial statements have been prepared using accounting principles generally accepted in the United States of America (“GAAP”). The consolidated financial statements include the results of the Company and its controlled subsidiaries. Third-party holdings of equity interests in the Company’s subsidiaries that are less than controlled represent noncontrolling interests. Intercompany accounts and transactions have been eliminated in the consolidated financial statements.

Reclassifications

Certain prior period amounts included in the 2018 consolidated balance sheet has been reclassified to conform to the current year presentation. Specifically, in the 2018 consolidated balance sheet Inventory, net has been combined with Prepaid expenses and other current assets and Obligations for acquisition of businesses has been combined with Other accrued expenses and current liabilities.

Use of Estimates

Use of estimates

The preparation of the consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the financial statements, and reported amounts of revenue and expenses during the reporting periods. On an ongoing basis, management evaluates its significant estimates including the stand alone selling price, or SSP, for each distinct performance obligation included in customer contracts with multiple performance obligations, the incremental borrowing rate used in the valuation of lease liabilities, fair value of convertible senior notes, provision for doubtful accounts, tax valuation allowances, liabilities for uncertain tax provisions, impairment of goodwill and intangible assets, retirement obligations, useful lives of intangible assets, revenue for fixed price contracts, valuation of common stock, and stock-based compensation. Actual results could differ from those estimates.

Delaware Conversion

On October 5, 2017, the Company became a Delaware corporation and effected a four-for-one stock split of its common stock. On the effective date of the Company becoming a Delaware corporation, (i) each share of outstanding common stock was increased to four shares of common stock, par value $0.0001 per share, (ii) the number of shares of common stock issuable under each outstanding option to purchase common stock was increased on a four-for-one basis, (iii) the exercise price of each outstanding option to purchase common stock was reduced on a four-for-one basis, and (iv) the redemption price of each outstanding put option was reduced on a four-for-one basis. All share and per share information referenced throughout the consolidated financial statements and notes thereto have been retroactively adjusted to reflect this stock split.

In connection with the Company becoming a Delaware corporation, 2,495,752 shares of Class B common stock, held by holders of less than 3% of Class B common stock immediately prior to the conversion, converted into Class A common stock.

Pursuant to the Company’s Delaware certificate of incorporation, the Company’s authorized capital consists of 513,796,572 shares of Class A common stock, 41,203,428 shares of Class B common stock and 45,000,000 shares of preferred stock.

Foreign Currency Translation

Foreign currency translation

The functional currency of the Company’s foreign subsidiaries is their respective local currency. The assets and liabilities of the subsidiaries are translated to U.S. dollars at the exchange rate on the balance sheet date. Equity balances and transactions are translated using historical exchange rates. Revenues and expenses are translated at the average exchange rate during the period. Translation adjustments arising from the use of differing exchange rates from period to period are recorded as a component of accumulated other comprehensive loss within stockholders’ equity.

All assets and liabilities denominated in a currency other than the functional currency are remeasured into the functional currency with gains and losses recognized in foreign currency losses, net, in the consolidated statements of operations. The Company has no transactions which hedge purchase commitments and no intercompany balances which are designated as being of a long-term investment in nature.

Revenue Recognition and Cost of Revenue

Revenue recognition

The Company generates revenue from our Software and CES segments and our other businesses. Revenue is recognized by identifying a contract with a customer, identifying the performance obligations in the contract, determining the transaction price, allocating the

transaction price to the performance obligations in the contract, and recognizing revenue when (or as) the Company satisfies a performance obligation.

Software

Software revenue includes product revenue from software product licensing arrangements, related services consisting of software maintenance and support in the form of post-contract customer support (PCS or maintenance) and professional services such as consulting and training services. To a much lesser extent, software revenue also includes revenue from the sale of hardware products, primarily as a result of business acquisitions.

Software products are sold to customers primarily under a term-based software licensing model and to a lesser degree, perpetual software licenses. The Company enters into contracts that include combinations of products, maintenance and services, which are accounted for as separate performance obligations with differing revenue recognition patterns.

Most term-based software license agreements include the Company’s patented units-based subscription model which allows customers to license a pool of units for their organizations, providing individual users flexible access to the Company’s entire portfolio of engineering software applications as well as to its growing portfolio of partner products. The amount of software usage is limited by the number of the units licensed by the customer. Revenue from these arrangements is fixed (based on the units licensed) and is not based on actual customer usage of each software product.

Revenue from term-based software licenses is classified as license software revenue. Term-based licenses are sold only as a bundled arrangement that includes the rights to a term software license and PCS, which includes unspecified technical enhancements and customer support. Maximizing the use of observable inputs, the Company determined that a majority of the estimated standalone selling price of the term-based license is attributable to the term license and a minority is attributable to the PCS. The license component is recognized as revenue upon the later of delivery of the licensed product or the beginning of the license period. The PCS is classified as maintenance revenue and is recognized ratably over the term of the contract, as the Company provides the PCS benefit over time.

In addition to term-based software licenses, the Company sells perpetual licenses. Typically, the Company’s perpetual licenses are sold with PCS, which includes unspecified technical enhancements and customer support. Revenue from the software component is classified as license software revenue and is recognized upon the later of delivery of the licensed product or the beginning of the license period. The Company allocates value in bundled perpetual and PCS arrangements based on the standalone selling prices of the perpetual license and PCS. Revenue from PCS is classified as maintenance revenue and is recognized ratably over the term of the contract, as the Company satisfies the PCS performance obligation over time.

Revenue from training, consulting and other services is recognized as the services are performed. For contracts in which the service consists of a single performance obligation, such as providing a training class to a customer, the Company recognizes revenue upon completion of the performance obligation. For service contracts that are longer in duration and often include multiple performance obligations (for example, both training and consulting), the Company measures the progress toward completion of the obligations and recognizes revenue accordingly. In measuring progress towards the completion of performance obligations, the Company typically utilizes output-based estimates for services with contractual billing arrangements that are not based on time and materials, and estimates output based on the total tasks completed as compared to the total tasks required for each work contract. Input-based estimates are utilized for services that involve general consultations with contractual billing arrangements based on time and materials, utilizing direct labor as the input measure.

The Company also executes arrangements through indirect channel partners in which the channel partners are authorized to market and distribute the Company's software products to end users of the Company's products and services in specified territories. In sales facilitated by channel partners, the channel partner generally bears the risk of collection from the end-user customer. The Company recognizes revenue from transactions with channel partners when the channel partner submits a purchase commitment, collectability from the channel partner is probable, and the performance obligation was met, at a point in time or over time as appropriate, provided that all other revenue recognition criteria are satisfied. Revenue from channel partner transactions is the amount remitted to the Company by the channel partners. This amount includes a fee for PCS that is compensation for providing technical enhancements and the second level of technical support to the end user, which is recognized over the period that PCS is to be provided. The Company does not offer right of return, product rotation or price protection to any of its channel partners.

Non-income related taxes collected from customers and remitted to governmental authorities are recorded on the consolidated balance sheet as accounts receivable, net and other accrued expenses and current liabilities. These amounts are reported on a net basis in the consolidated statements of operations and do not impact reported revenues or expenses. Certain hardware revenue is included within software revenue and is recognized when all revenue recognition criteria stated above are met, which is generally when the products are delivered to end customers.

Software related services

Consulting services from product design and development projects are considered distinct performance obligations and are provided to customers on a time-and-materials, or T&M, or fixed-price basis. Altair recognizes services revenue from our T&M contracts using input-based estimates, utilizing direct labor and contractually agreed-upon hourly rates as the input measure. For fixed-price contracts, software services revenue is recognized over time using a method that measures the extent of progress towards completion of a performance obligation, generally using a cost-input method where revenue is recognized based on the proportion of total cost incurred to estimated total costs at completion. If output or input measures are not available or cannot be reasonably estimated, revenue is recognized upon completion of the services.

Client engineering services

CES revenue is derived from our hiring of engineers and data scientists for placement at a customer site for specific customer-directed assignments. These professional services are considered distinct performance obligations and are provided to customers on a T&M basis. We recognize client engineering services revenue based upon hours worked and contractually agreed-upon hourly rates.

Other

Other revenue includes product revenue from the sale of LED products primarily for the replacement of fluorescent tubes. Revenue from the sale of LED products for the replacement of fluorescent tubes is recognized when all revenue recognition criteria stated above are met, which is generally when the products are delivered to resellers or to end customers. Sales returns, which reduce revenue, are estimated using historical experience.

Cost of revenue

Cost of software

Cost of software revenue consist of expenses related to software licensing, hardware sales and customer support. Significant expenses include employee related costs for support team members, travel costs, and royalties for third-party software products available to customers through the Company’s products or as part of the Company’s Partner Alliance Program, or APA.

Cost of client engineering services

Cost of engineering services revenue consists primarily of employee compensation and related costs. We employ and pay them only for the duration of the placement.

Cost of other

Cost of other revenue includes the cost of LED lighting products and freight related to products sold to retail and commercial sales channels.

Cash, Cash Equivalents and Restricted Cash

Cash, cash equivalents and restricted cash

The Company considers all highly liquid investments with original or remaining maturities of 90 days or less at the date of purchase to be cash equivalents. Cash and cash equivalents are recorded at cost, which approximates fair value.

Restricted cash is included in other long-term assets on the consolidated balance sheets. The following table provides a reconciliation of cash, cash equivalents and restricted cash reported in the consolidated balance sheets that sum to the total of the amounts reported in the consolidated statements of cash flows (in thousands):

	December 31,
	2019		2018
Cash and cash equivalents	$	223,117	$	35,345
Restricted cash included in other long-term assets		380		340
Total cash, cash equivalents, and restricted cash	$	223,497	$	35,685

Restricted cash represents amounts required for a contractual agreement with an insurer for the payment of potential health insurance claims, and term deposits for bank guarantees.

Accounts Receivable, Net

Accounts receivable, net

Accounts receivable, net consisted of the following (in thousands):

	December 31,
	2019		2018
Accounts receivable, trade	$	100,461	$	93,073
Contract assets		4,523		3,730
Accounts receivable, net	$	104,984	$	96,803

An allowance for doubtful accounts is recorded when amounts are determined to be uncollectible based on specific identification of customer circumstances, age of the receivable and other available information. Accounts are written off when it becomes apparent that such amounts will not be collected. Generally, the Company does not require collateral or charge interest on accounts receivable. Accounts receivable were reported net of an allowance for doubtful accounts of $1.4 million and $1.2 million at December 31, 2019 and 2018, respectively. Activity in the allowance for doubtful accounts was as follows (in thousands):

	For the year ended December 31,
	2019			2018			2017
Balance, beginning of year	$	(1,150	)	$	(798	)	$	(565	)
Provision charged to expense		(671	)		(394	)		(610	)
Write-offs, net of recoveries		413			3			414
Effects of foreign currency translation		(7	)		39			(37	)
Balance, end of year	$	(1,415	)	$	(1,150	)	$	(798	)

Concentrations of Credit Risk

Concentrations of credit risk

The Company’s financial instruments that are potentially subject to concentrations of credit risk consist primarily of cash and trade receivables. The risk with respect to trade receivables is partially mitigated by the diversity, both by geography and by industry, of the Company’s customer base. The Company’s accounts receivable is derived from sales to a large number of direct customers and resellers around the world. Sales to customers within the automotive industry accounted for approximately 40%, 45%, and 50% of the Company’s 2019, 2018 and 2017 revenue, respectively, with no other industry representing more than 10% of revenue. No individual customer accounted for 10% or more of revenue in the years ended December 31, 2019, 2018 or 2017.

Inventory

Inventory consist of finished goods and is stated at the lower of cost and net realizable value. Cost is determined using the first-in, first-out method. Net realizable value is the estimated selling prices in the ordinary course of business, less reasonable predictable costs of completion, disposal and transportation. The valuation of inventory requires management to estimate excess inventory as well as inventory that is not of saleable quality. The determination of obsolete or excess inventory requires management to estimate market conditions and future demand for the Company’s products. Inventory was $2.4 million and $2.0 million at December 31, 2019 and 2018, respectively, and is included in prepaid expenses and other current assets in the consolidated balance sheets.

Property and Equipment, Net

Property and equipment, net

Property and equipment are stated at cost, less accumulated depreciation and amortization. Equipment held under capital leases are stated at the present value of minimum lease payments less accumulated amortization. Depreciation is calculated using the straight-line method over the estimated useful lives of the assets. Leasehold improvements and assets acquired under capital leases are amortized over the lease term or the estimated useful life of the related asset or improvement, whichever is shorter.

Expenditures for maintenance and repairs are charged to expense in the period incurred. Major expenditures for betterments are capitalized when they meet the criteria for capitalization. When assets are retired or otherwise disposed of, the cost and accumulated depreciation are removed from the accounts and any resulting gain or loss is reflected in the consolidated statements of operations in the period realized.

Software Development Costs

Software development costs

Software development costs incurred prior to the establishment of technological feasibility are expensed as incurred. Technological feasibility is established upon the completion of a detailed program design. Capitalization of software development costs begins upon the establishment of technological feasibility and ends when the product is available for general release. Generally, the time between the establishment of technological feasibility and commercial release of software is short. As such, all internal software development costs

have been expensed as incurred and included in research and development expense in the accompanying consolidated statements of operations.

Impairment of Long-Lived Assets

Impairment of long-lived assets

Long-lived assets, such as property and equipment, and definite-lived intangible assets, including developed technology and customer relationships, are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. If circumstances require a long-lived asset or asset group to be tested for possible impairment, the Company compares the undiscounted future cash flows expected to be generated by that asset or asset group to its carrying amount. If the carrying amount of the long-lived asset or asset group is not recoverable on an undiscounted cash flow basis, an impairment charge is recognized to the extent that the carrying amount exceeds its fair value. Fair value is determined through various valuation techniques, including discounted cash flow models and third-party independent appraisals. No impairment losses were recognized in 2019, 2018, or 2017.

Goodwill and Other Indefinite-Lived Intangible Assets

Goodwill and other indefinite-lived intangible assets

Goodwill represents the excess of the consideration transferred for an acquired entity over the estimated fair values of the net tangible assets and the identifiable assets acquired. As described in Note 4—Acquisitions and disposals, the Company has recorded goodwill in connection with certain acquisitions. Goodwill and other indefinite-lived intangible assets are not amortized, but rather are reviewed for impairment annually or more frequently if facts or circumstances indicate that the carrying value may not be recoverable.

The Company has determined that there is one reporting unit with goodwill subject to goodwill impairment testing. An entity has the option to perform a qualitative assessment to determine whether it is more likely than not that the fair value of the reporting unit is less than its carrying amount prior to performing the quantitative two-step impairment test.

The Company has the option to first assess qualitative factors to determine whether the existence of events or circumstances leads to a determination that it is more likely than not that the fair value of a reporting unit is less than its carrying amount prior to performing the quantitative two-step impairment test. The qualitative assessment evaluates various events and circumstances, such as macro-economic conditions, industry and market conditions, cost factors, relevant events and financial trends that may impact a reporting unit’s fair value. If, after assessing the totality of events or circumstances, an entity determines it is not more likely than not that the fair value of a reporting unit is less than its carrying amount, including goodwill, then additional impairment testing is not required. However, if an entity concludes otherwise, then it is required to perform the two-step goodwill impairment test.

The impairment test involves comparing the estimated fair value of a reporting unit with its book value, including goodwill. If the estimated fair value exceeds book value, goodwill is considered not to be impaired. If, however, the fair value of the reporting unit is less than book value, then an impairment loss is recognized in an amount equal to the amount that the book value of the reporting unit exceeds its fair value, not to exceed the total amount of goodwill allocated to the reporting unit.

The Company performs its annual impairment review of goodwill in the fourth quarter of each year and when a triggering event occurs between annual impairment dates. For 2018, the Company performed a quantitative assessment of goodwill and determined that the fair value of the reporting unit exceeded its carrying amount, as such, step two does not need to be performed. Accordingly, the Company determined that its goodwill was not impaired. For 2019, the Company performed a qualitative assessment of goodwill and determined that it was not more likely than not that the fair value of its reporting unit with goodwill was less than the carrying amounts. Accordingly, the Company determined that its goodwill was not impaired.

The Company performs its annual impairment review of indefinite-lived intangibles in the fourth quarter of each year and when a triggering event occurs between annual reporting dates. In 2019, the Company performed a qualitative assessment of indefinite-lived trade names and determined there was no indication of impairment. Accordingly, no impairment charges were recognized in 2019. During the quarter ended September 30, 2018, the Company performed a test of indefinite-lived trade names. This test was triggered by the Company’s decision during the quarter to rename and rebrand certain products in the Software segment. Upon completion of the impairment test, the Company recorded an impairment charge of $0.6 million which is included in other operating income for the year ended December 31, 2018.

Receivable for R&D Credit

Receivable for R&D credit

The French government provides a research and development (“R&D”) tax credit known as Credit Impôt Recherche, or CIR, in order to encourage Companies to invest in R&D. The tax credit is deductible from the French income tax and any excess is carried forward for three years. After three years, any unused credit may be reimbursed to the Company by the French government. As of December 31, 2019, the Company had approximately $12.1 million receivable from the French government related to CIR, of which $2.5 million is recorded in income tax receivable and the remaining $9.6 million is recorded in other long-term assets. As of December 31, 2018, the Company had approximately $11.7 million receivable from the French government related to CIR, of which $2.6 million was recorded

in income tax receivable and the remaining $9.1 million was recorded in other long-term assets. CIR is subject to customary audit by the French tax authorities.

Derivative Financial Instruments

Derivative financial instruments

The Company may use derivative financial instruments, primarily interest rate swap contracts or foreign currency contracts, to hedge its exposure to interest rate or foreign exchange risk. Such derivative financial instruments are initially recorded at fair value on the date on which a derivative contract is entered into and are subsequently remeasured to fair value at period end. Any gains or losses arising from changes in fair value on derivative contracts during the year are recorded in other (income) expense, net in the consolidated statement of operations. Hedge accounting has not been applied.

Income Taxes

Income taxes

The Company accounts for income taxes under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax basis and for operating loss and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in income in the period that includes the enactment date. The Company records net deferred tax assets to the extent it believes that these assets will more likely than not be realized. These deferred tax assets are subject to periodic assessments as to recoverability and if it is determined that it is more likely than not that the benefits will not be realized, valuation allowances are recorded which increase the provision for income taxes. In making such determination, the Company considers all available positive and negative evidence, including historical taxable income, projected future taxable income, the expected timing and reversal of existing temporary differences, ability to carryback losses, and tax planning strategies. If based upon the evidence, it is more likely than not that the deferred tax asset will not be realized, a valuation allowance is recorded. A valuation allowance is recognized to reduce deferred tax assets to the amount that management believes is more likely than not to be realized.

The Company applies a more-likely-than-not recognition threshold to its accounting for tax uncertainties. The Company reviews all of its tax positions and makes determinations as to whether its tax positions are more likely than not to be sustained upon examination by the relevant taxing authorities. Only those benefits that have a greater than fifty percent likelihood of being sustained upon examination by taxing authorities are recognized. Interest and penalties related to uncertain tax positions are recorded in the provision for income taxes in the consolidated statements of operations.

Research and Development Costs

Research and development costs

Research and development costs are expensed as incurred. Research and development expenses consist primarily of salaries and benefits of research and development employees and costs incurred related to the development of new software products and significant enhancements and engineering changes to existing software products. Research and development expenses were $117.5 million, $97.6 million, and $93.2 million for the years ended December 31, 2019, 2018 and 2017, respectively.

Advertising Costs

Advertising costs

Advertising costs are expensed as incurred. Advertising expenses were $4.5 million, $4.4 million and $3.5 million for the years ended December 31, 2019, 2018, and 2017, respectively.

Mezzanine Equity

Mezzanine equity

In 2017, the Company issued 200,000 shares of Class A common stock to a third party as partial consideration for the purchase of developed technology. These shares have a put right that can be exercised by the holder five years from date of purchase at $12.50 per share that requires the shares to be recorded at fair value and classified as mezzanine equity in the consolidated balance sheet. As of December 31, 2017, the Company concluded that it is no longer probable that the put option will be exercised as the put value is substantially below market value and subsequent adjustment is not required.

Classification of the instrument shall remain as mezzanine equity until one of the following three events take place; 1) shares are sold on open market; 2) a redemption feature lapses; or 3) there is a modification of the terms of the instrument. As none of these events have taken place as of December 31, 2019, the classification remains as mezzanine equity.

Leases

The Company determines if an arrangement is a lease at inception. Operating leases are included in operating lease right-of-use (“ROU”) assets, current portion of operating lease liabilities, and operating lease liabilities, net of current portion on the Company’s consolidated balance sheets. Finance leases are included in property and equipment, current portion of long-term debt, and long-term debt, net of current portion on the consolidated balance sheets.

Stock-Based Compensation

Stock-based compensation

Employee stock-based awards, consisting of stock options or restricted stock units (RSUs) expected to be settled by issuing shares of Class A common stock, are recorded as equity awards. The fair value of these awards on the date of grant is measured using the Black-Scholes option pricing model. The Company expenses the grant date fair value of its time-vested stock options subject to graded vesting using the straight-line method over the applicable service period. The fair value of RSUs, is measured using the fair value of the Company’s Class A common stock on the date of the grant. The fair value of RSUs is recognized as expense on a straight-line basis over the requisite service period, which is generally four years.

Employee stock-based awards, which consisted of stock options with repurchase features that allowed them to be settled in cash at a purchase price that was less than the current fair value, were considered liability-based awards. These awards were initially recorded at fair value and remeasured to fair value at the end of each reporting period until settled. During 2017, the Company changed its accounting policy to measure the fair value of its liability awards using the Black-Scholes option pricing model as a result of the Company no longer meeting the definition of a non-public entity. The impact of the change in accounting policy was immaterial to the financial statements. Upon IPO effectiveness later in 2017, the repurchase feature was terminated and resulted in a modification of the option awards and these options were accounted for as equity awards post the Company’s IPO.

Other Income, Net

Other income, net

Other income, net consists of the following (in thousands):

	Year ended December 31,
	2019			2018			2017
Foreign exchange loss (gain)	$	745		$	(626	)	$	1,254
Other		(2,297	)		(1,954	)		(260	)
Other (income) expense, net	$	(1,552	)	$	(2,580	)	$	994

Recent Accounting Guidance

Recent accounting guidance

Accounting standards adopted

Leases —In February 2016, the Financial Accounting Standard Board, or “FASB”, issued Accounting Standards Update, or “ASU”, No. 2016-02, Leases (ASC 842). This standard amends various aspects of existing accounting guidance for leases, including the recognition of a right-of-use (ROU) asset and a lease liability on the balance sheet for all leases with terms longer than 12 months. The Company adopted ASU 2016-02 and its related amendments, on January 1, 2019 and elected the optional transition method and the package of practical expedients on adoption. Accordingly, the prior period comparative information has not been restated and continues to be reported under the accounting guidance in effect for those periods, including the disclosure requirements. The most significant impact of the adoption of ASC 842 was the recognition of ROU assets and lease liabilities for operating leases on the Company’s consolidated balance sheet. On adoption, the Company recognized operating liabilities associated with leases of $30.1 million and corresponding ROU assets of $29.1 million, based on the present value of the remaining minimum rental payments under current leasing standards for existing operating leases. See Note 8 – Leases for further discussion. The Company’s accounting for finance leases (previously referred to as capital leases prior to the adoption of ASC 842) remained substantially unchanged. The standard had no impact on the Company’s consolidated net income or cash flows.

Goodwill Impairment —In January 2017, the FASB issued ASU No. 2017-04, Intangibles – Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment, which simplifies accounting for goodwill impairments by eliminating step two from the goodwill impairment test. This guidance is effective for annual or interim goodwill impairment tests in fiscal years beginning after December 15, 2019. Early adoption is permitted for interim and annual goodwill impairment tests performed on testing dates after January 1, 2017. The Company early adopted this guidance on October 1, 2019, and it did not have a material effect on the Company’s consolidated financial statements.

Derivatives and Hedging – In August 2017, the FASB issued ASU 2017-12, Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities. This ASU amends the guidance with the objective of improving the financial reporting of hedging relationships to better portray the economic results of an entity’s risk management activities in its financial statements. In addition, this ASU amends the current guidance to simplify the application of the hedge accounting guidance. The Company adopted ASU 2017-12 on January 1, 2019. The adoption of this guidance did not have a material effect on the Company’s consolidated financial statements.

Comprehensive Income – In February 2018, the FASB issued ASU 2018-02, Income Statement — Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income (AOCI), which gives entities the option to reclassify to retained earnings the tax effects resulting from the Tax Cuts and Jobs Act, or the “Tax Act”, related to items in AOCI that the FASB refers to as having been stranded in AOCI. The Company adopted this guidance on January 1, 2019 and elected not to reclassify amounts stranded in AOCI. The Company reclassifies taxes from AOCI to earnings as the items to which the tax effects relate are similarly reclassified. The adoption of ASU 2018-02 did not have a material effect on the Company’s consolidated financial statements.

Stock Compensation – In June 2018, the FASB issued ASU 2018-07, Compensation – Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting. This ASU simplifies the accounting for share-based payments to nonemployees by aligning it with the accounting for share-based payments to employees, with certain exceptions. The Company adopted this guidance on January 1, 2019, and it did not have a material effect on the Company’s consolidated financial statements.

Accounting standards not yet adopted

Credit Losses – In June 2016, the FASB issued ASU 2016-13, Financial Instruments — Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. The ASU significantly changes how entities will measure credit losses on most financial assets. This guidance is effective for annual periods beginning after December 15, 2019, and interim periods therein; early adoption is permitted. The Company is currently evaluating the impact of this new guidance on its consolidated financial statements and related disclosures and does not expect this guidance to have a material effect on its consolidated financial statements.

Fair Value – In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement. This ASU modifies the disclosure requirements for fair value measurements, by removing, modifying, or adding certain disclosures. The amendments are effective for fiscal years, and interim reporting periods within those fiscal years, beginning after December 15, 2019. Early adoption is permitted for any removed or modified disclosures. The Company is currently evaluating the impact of the new guidance on its consolidated financial statements and related disclosures and does not expect this guidance to have a material effect on its consolidated financial statements.

Retirement Benefits – In August 2018, the FASB issued ASU 2018-14, Compensation – Retirement Benefits- Defined Benefit Plans – General (Subtopic 715-20): Disclosure Framework – Changes to the Disclosure Requirements for Defined Benefit Plans. This ASU modifies the disclosure requirements for defined benefit pension or other postretirement plans. The amendments are effective for fiscal years ending after December 15, 2020; early adoption is permitted. The Company is currently evaluating the impact of the new guidance on its consolidated financial statements and related disclosures and does not expect this guidance to have a material effect on its consolidated financial statements.

Intangibles – In August 2018, the FASB issued ASU 2018-15, Intangibles – Goodwill and Other – Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That is a Service Contract. This ASU clarifies and aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. The amendments are effective for fiscal years beginning after December 15, 2019, and interim periods within those fiscal years; early adoption is permitted. The Company is currently evaluating the impact of the new guidance on its consolidated financial statements and related disclosures.

Income Taxes – In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes. This ASU simplifies the accounting for income taxes by removing certain exceptions to the general principles in Topic 740 and improves consistent application of GAAP for other areas of Topic 740 by clarifying and amending existing guidance. The amendments are effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020; early adoption is permitted. The Company is currently evaluating the impact of the new guidance on its consolidated financial statements and related disclosures and does not expect this guidance to have a material effect on its consolidated financial statements.

Fair Value Measurements

12 Months Ended

Dec. 31, 2019

Fair Value Disclosures [Abstract]

Fair Value Measurements

10. Fair value measurements

The accounting guidance for fair value, among other things, defines fair value, establishes a consistent framework for measuring fair value and expands disclosure for each major asset and liability category measured at fair value on either a recurring or nonrecurring basis. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability (an exit price) in an orderly transaction between market participants at the reporting date. The framework for measuring fair value consists of a three-level valuation hierarchy that prioritizes the inputs to valuation techniques used to measure fair value based upon whether such inputs are observable or unobservable. Observable inputs reflect market data obtained from independent sources, while unobservable inputs reflect market assumptions made by the reporting entity. The three-level hierarchy for the inputs to valuation techniques is briefly summarized as follows:


Level 1—	Quoted prices in active markets for identical assets and liabilities at the measurement date;

Level 2—	Observable inputs, other than the quoted prices in active markets, that are observable either directly or indirectly; and

Level 3—	Unobservable inputs in which there is little or no market data, which require the reporting entity to develop its own assumptions.

An asset’s or liability’s fair value measurement level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. Valuation techniques used need to maximize the use of observable inputs and minimize the use of unobservable inputs.

The carrying value of cash and cash equivalents, accounts receivable and accounts payable approximate fair value due to their short maturities. Interest on the Company’s long-term debt is at a variable rate, and as such the debt obligation outstanding approximates fair value.

The carrying value of the Company’s derivative financial instruments are measured at fair value on a recurring basis. The fair value of derivatives is determined based on inputs derived from or corroborated by observable market data pertaining to relevant interest rates and is considered a level 2 fair value measurement. See Note 11—Financial instruments for additional information regarding the use and fair value of derivatives.

The carrying value of the Company’s Convertible Notes are at face value less unamortized debt discount and issuance costs. The estimated fair values of the Convertible Notes, which the Company has classified as Level 2 financial instruments, were determined based on quoted bid prices of the Convertible Notes on the last trading day of each reporting period. At December 31, 2019, the fair value of the Convertible Notes was $236.1 million, and is presented for required disclosure purposes only. For further information on the Convertible Notes see Note 7. – Debt.

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

Beginning balance at Dec. 31, 2016

Leases - Schedule of Components of Lease Cost (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($)
Leases [Abstract]
Operating lease cost	$ 13,287
Finance lease cost:
Amortization of ROU assets	525
Interest on lease liabilities	21
Total finance lease cost	$ 546

Income Taxes - Summary of Changes to Valuation Allowance Balance (Detail) - Valuation Allowance of Deferred Tax Assets [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Valuation Allowance [Line Items]
Balance at beginning of year	$ 78,155	$ 56,761	$ 4,153
Additions charged to expense	18,138	21,544	49,859
Other	(11,937)	(150)	2,749
Balance at end of year	$ 84,356	$ 78,155	$ 56,761

Supplemental Quarterly Financial Information (Unaudited) - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Sep. 30, 2018	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Supplemental Quarterly Financial Information [Line Items]
Income recognized in non-recurring adjustment for change in estimated legal expenses		$ 2.0	$ 2.0	$ 2.0
Building [Member]
Supplemental Quarterly Financial Information [Line Items]
Gain on sale of property and equipment	$ 4.4

Consolidated balance sheets (Parenthetical) - $ / shares	Dec. 31, 2019	Dec. 31, 2018
Preferred stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	45,000,000	45,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Class A Common Stock [Member]
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	513,796,572	513,797,000
Common stock, shares issued	41,271,000	38,349,000
Common stock, shares outstanding	41,271,000	38,349,000
Class B Common Stock [Member]
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	41,203,428	41,203,000
Common stock, shares issued	31,131,000	32,171,000
Common stock, shares outstanding	31,131,000	32,171,000

Consolidated statement of changes in stockholders' equity (deficit) - USD ($)
shares in Thousands, $ in Thousands

Total

IPO [Member]

Common Stock

Class A Common Stock [Member]

Common Stock

Class A Common Stock [Member]

IPO [Member]

Common Stock

Class B Common Stock [Member]

Common Stock

Class B Common Stock [Member]

IPO [Member]

Additional Paid-in Capital [Member]

IPO [Member]

Accumulated Deficit [Member]

Accumulated Other Comprehensive Loss [Member]

Total Altair Engineering' Inc. Stockholders' Equity (Deficit) [Member]

IPO [Member]

Non-controlling Interest [Member]

$ (33,762)

$ 1

$ 4

$ 39,688

$ (66,201)

$ (7,264)

$ (33,772)

$ 10

Beginning balance (in shares) at Dec. 31, 2016

8,900

41,204

Issuance of common stock (in shares)

(101,941)

^[1]

(101,941)

Issuance of common stock

$ 114,438

$ 1

$ 114,437

$ 114,438

13,800

(2,200)

Shares converted upon Delaware incorporation (in shares)

2,496

(2,496)

2001 ISO Plan modification

66,510

Issuance of common stock for acquisitions

8,712

Issuance of common stock for acquisitions (in shares)

988

Purchase of noncontrolling interests

(29)

(19)

$ (10)

Amortization of mezzanine equity

(8)

Exercise of stock options

1,792

Exercise of stock options (in shares)

541

Foreign currency translation, net of tax

1,044

2,351

(159)

Ending balance at Dec. 31, 2017

58,948

$ 2

$ 4

232,156

(168,142)

(5,072)

58,948

Ending balance (in shares) at Dec. 31, 2017

26,725

36,508

Cumulative effect of an accounting change

77,744

Follow-on public offering, net of offering costs of $370

15,535

135,201

$ 1

$ (1)

135,201

Follow-on public offering, net of offering costs of $370 (shares)

5,731

(1,675)

Adjustment for acquisitions

(96)

Issuance of common stock for acquisitions

8,681

Issuance of common stock for acquisitions (in shares)

145

Exercise of stock options

2,077

$ 1

2,076

2,077

Exercise of stock options (in shares)

3,086

Conversion from Class B to Class A common stock

2,662

(2,662)

Foreign currency translation, net of tax

1,814

(5,449)

(769)

Ending balance at Dec. 31, 2018

293,686

$ 4

$ 3

379,832

(74,863)

(11,290)

293,686

Ending balance (in shares) at Dec. 31, 2018

38,349

32,171

Equity component of convertible senior notes, net of issuance costs

(7,542)

50,009

Issuance of common stock for acquisitions

7,637

Issuance of common stock for acquisitions (in shares)

250

Exercise of stock options and other

1,510

Exercise of stock options and other (in shares)

1,571

Vesting of restricted stock (in shares)

Conversion from Class B to Class A common stock

1,040

(1,040)

Foreign currency translation, net of tax

7,645

1,895

(133)

Ending balance at Dec. 31, 2019

$ 354,707

$ 4

$ 3

$ 446,633

$ (82,405)

$ (9,528)

$ 354,707

Ending balance (in shares) at Dec. 31, 2019

41,271

31,131

[1]	The year ended December 31, 2017 has been reported under ASC 605 and has not been adjusted under the modified retrospective approach of ASC 606. See Note 3 – Revenue from contracts with customers for the effect of the adoption of ASC 606 on the Company’s consolidated financial statements.

Leases (Tables)

12 Months Ended

Dec. 31, 2019

Leases [Abstract]

Schedule of Components of Lease Cost

The components of lease cost were as follows (in thousands):

	For the Year Ended December 31,
	2019
Operating lease cost	$	13,287

Finance lease cost:
Amortization of ROU assets	$	525
Interest on lease liabilities		21
Total finance lease cost	$	546

Schedule of Supplemental Balance Sheet Information Related to Lease Liabilities

Supplemental balance sheet information related to lease liabilities at December 31, 2019, was as follows:

(in thousands, except lease term and discount rate)
Operating leases:
Operating lease ROU assets	$	28,134

Current portion of operating lease liabilities	$	9,141
Operating lease liabilities, net of current portion		20,174
Total operating lease liabilities	$	29,315

Weighted average remaining lease term	4.2
Weighted average discount rate		5.6	%

Finance leases:
Property and equipment	$	2,745
Accumulated depreciation		(1,447	)
Property and equipment, net	$	1,298

Current portion of long-term debt	$	430
Long-term debt, net of current portion		744
Total finance lease liabilities	$	1,174

Weighted average remaining lease term		2.7
Weighted average discount rate		3.5	%

Schedule of Supplemental Cash Flow Information Related to Leases

Supplemental cash flow information related to leases for the year ended December 31, 2019, was as follows (in thousands):

Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$	(11,355	)
Operating cash flows from finance leases	$	(46	)
Financing cash flows from finance leases	$	(438	)

ROU assets obtained in exchange for lease obligations:
Operating leases	$	11,251
Finance leases	$	632

Schedule of Maturities of Operating Lease Liabilities

Maturities of operating lease liabilities at December 31, 2019, were as follows (in thousands):

Year ending December 31,
2020	$	10,444
2021		8,177
2022		5,768
2023		3,684
2024		1,730
Thereafter		3,055
Total lease payments		32,858
Less: imputed interest		3,543
Total operating lease liabilities	$	29,315

(Loss) Income Per Share

12 Months Ended

Dec. 31, 2019

Earnings Per Share [Abstract]

(Loss) Income Per Share

15. (Loss) income per share

Basic (loss) income per share attributable to common stockholders is computed using the weighted average number of shares of common stock outstanding for the period, excluding stock options and restricted stock units (“RSUs”). Diluted (loss) income per share attributable to common stockholders is based upon the weighted average number of shares of common stock outstanding for the period and potentially dilutive common shares, including the effect of stock options and RSUs under the treasury stock method. The following table sets forth the computation of the numerators and denominators used in the basic and diluted (loss) income per share amounts (in thousands, except per share data):

	Year ended December 31,
	2019			2018		2017
Numerator:
Net (loss) income	$	(7,542	)	$	15,535	$	(101,941	)
Denominator:
Denominator for basic (loss) income per share— weighted average shares		71,544			67,468		52,466
Effect of dilutive securities, stock options and RSUs		—			7,410		—
Denominator for dilutive (loss) income per share		71,544			74,878		52,466
Net (loss) income per share attributable to common stockholders, basic	$	(0.11	)	$	0.23	$	(1.94	)
Net (loss) income per share attributable to common stockholders, diluted	$	(0.11	)	$	0.21	$	(1.94	)

The computation of diluted (loss) income per share does not include shares that are anti-dilutive under the treasury stock method because their exercise prices are higher than the average fair value of the Company’s stock during the year or due to a net loss in the year. For the year ended December 31, 2019, there were 5.7 million potentially anti-dilutive shares, which were excluded from the computation of (loss) income per share. For the year ended December 31, 2018, there were no anti-dilutive shares, which were excluded from the computation of (loss) income per share. For the year ended December 31, 2017, there were 10.2 million potentially anti-dilutive shares, which were excluded from the computation of (loss) income per share.

The Company expects to settle the principal amount of the Convertible Notes (as defined in Note 7 in cash, and therefore, the Company uses the treasury stock method for calculating any potential dilutive effect of the Conversion Option (as defined in Note 7) on diluted net (loss) income per share, if applicable. The Conversion Option will have a dilutive impact on net income per share of common stock when the average market price of the Company’s Class A common stock for a given period exceeds the conversion price of the Convertible Notes of $46.50 per share. During the year ended December 31, 2019, the Company's weighted average common stock price was below the conversion price of the Convertible Notes.

Revenue from Contracts with Customers (Tables)

12 Months Ended

Dec. 31, 2019

Schedule of Disaggregation of Revenue

The Company disaggregates its software revenue by type of performance obligation and timing of revenue recognition as follows (in thousands):

	Year Ended December 31,
	2019 (ASC 606)		2018 (ASC 606)		2017 (ASC 605)⁽¹⁾
Software revenue:
Term licenses	$	201,881	$	168,909
Perpetual licenses		42,440		38,255
Maintenance		103,699		86,150
Professional services and other		18,682		11,047
Total software revenue	$	366,702	$	304,361	$	244,817

ASC 606 [Member]

Effect of Adoption of ASC 606 on Consolidated Statement of Operations

The following table presents the effect of the adoption of ASC 606 on the consolidated statement of operations (in thousands):

	Year Ended December 31, 2018
	Prior to adoption of ASC 606		Adjustments for ASC 606			As Reported
Revenue
Licenses	$	195,847	$	11,317		$	207,164
Gross profit	$	269,089	$	11,317		$	280,406
Operating expenses
Sales and marketing	$	80,613	$	(336	)	$	80,277
Total operating expenses	$	256,098	$	(336	)	$	255,762
Operating income	$	12,991	$	11,653		$	24,644
Income before income taxes	$	15,371	$	11,653		$	27,024
Income tax expense	$	10,829	$	660		$	11,489
Net income	$	4,542	$	10,993		$	15,535
Income per share:
Basic	$	0.07	$	0.16		$	0.23
Diluted	$	0.06	$	0.15		$	0.21

Debt

12 Months Ended

Dec. 31, 2019

Debt Disclosure [Abstract]

Debt

7. Debt

The carrying value of debt is as follows (in thousands):

	December 31,
	2019		2018
Convertible senior notes	$	230,000	$	—
Revolving credit facility		—		30,950
Obligations for finance leases		1,174		813
Other borrowings		—		75
Total debt		231,174		31,838
Less: unamortized debt discount		46,820		—
Less: unamortized debt issuance costs		5,686		90
Less: current portion of long-term debt		430		331
Long-term debt, net of current portion	$	178,238	$	31,417

Convertible senior notes

In June 2019, the Company issued $230.0 million aggregate principal amount of 0.25% convertible senior notes due in 2024 (the "Convertible Notes"), which includes the underwriters’ exercise in full of their option to purchase an additional $30.0 million principal amount of the Convertible Notes, in a public offering. The net proceeds from the issuance of the Convertible Notes were $221.9 million after deducting the underwriting discounts and commissions and issuance costs.

The Company entered into a First Supplemental Indenture relating to the issuance by the Company of the Convertible Notes (the “Supplemental Indenture”) supplementing the Indenture, dated June 10, 2019 (the “Base Indenture,” and together with the Supplemental Indenture, the “Indenture”), by and between the Company and U.S. Bank National Association, as trustee (the “Trustee”). The Indenture includes customary covenants and sets forth certain events of default after which the Convertible Notes may be declared immediately due and payable and sets forth certain types of bankruptcy or insolvency events of default involving the Company after which the Convertible Notes become automatically due and payable. The Convertible Notes are senior unsecured obligations of the Company.

The Convertible Notes bear interest at a rate of 0.25% per year, payable semi-annually in arrears on June 1 and December 1 of each year, commencing December 1, 2019. The Convertible Notes will mature on June 1, 2024, unless, earlier repurchased or redeemed by the Company or converted pursuant to their terms.

The Convertible Notes have an initial conversion rate of 21.5049 shares of the Company's Class A common stock per $1,000 principal amount of Convertible Notes, which is equivalent to an initial conversion price of approximately $46.50 per share of its Class A common stock. The conversion rate will be subject to adjustment upon the occurrence of certain events specified in the Indenture but will not be adjusted for any accrued and unpaid interest. In addition, upon the occurrence of a make whole fundamental change or a redemption period (each as defined in the Indenture), the Company will, in certain circumstances, increase the conversion rate by a specified number of additional shares for a holder who elects to convert its Convertible Notes in connection with such make whole fundamental change or during the relevant redemption period.

Holders of the Convertible Notes may convert all or any portion of their Convertible Notes at any time prior to the close of business on December 1, 2023, in integral multiples of $1,000 principal amount, only under the following circumstances:

•

During any calendar quarter commencing after the calendar quarter ending on September 30, 2019 (and only during such calendar quarter), if the last reported sale price of the Class A Common Stock for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price on each applicable trading day;

•

During the five business day period after any five consecutive trading day period (the “measurement period”) in which the trading price (as defined in the Indenture) per $1,000 principal amount of Convertible Notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price of the Class A Common Stock and the conversion rate on each such trading day;

•

If the Company calls any or all of the Convertible Notes for redemption (which the Company may not do prior to June 6, 2022), at any time prior to the close of business on the scheduled trading day immediately preceding the redemption date; or

•

Upon the occurrence of specified corporate events.

On or after December 1, 2023 until the close of business on the business day immediately preceding the maturity date, holders may convert their Convertible Notes at any time, regardless of the foregoing circumstances. Upon conversion, the Company may satisfy its conversion obligation by paying and/or delivering, as the case may be, cash, shares of Class A Common Stock or a combination of cash and shares of the Class A Common Stock, at the Company’s election, in the manner and subject to the terms and conditions provided in the Indenture.

During the quarter ended December 31, 2019, the conditions allowing holders of the Convertible Notes to convert were not met. Therefore, the Convertible Notes were classified as long-term debt on the consolidated balance sheet as of December 31, 2019.

As of December 31, 2019, the “if converted value” did not exceed the principal amount of the Convertible Notes since the closing sales price of the Company’s common stock was less than the conversion price of the Convertible Notes.

The Company accounts for the Convertible Notes as separate liability and equity components. The carrying amount of the liability component of the Convertible Notes was calculated by measuring the fair value of similar debt instruments that do not have an associated convertible feature. The Company determined the carrying amount of the liability component as the present value of its cash flows using a discount rate of approximately 5.5%. The estimated interest rate was applied to the Convertible Notes, which resulted in a fair value of the liability component of $178.2 million upon issuance, calculated as the present value of future contractual payments based on the $230.0 million aggregate principal amount. The excess of the principal amount of the liability component over its carrying amount, or the debt discount, is amortized to interest expense over the term of the Convertible Notes using the effective interest method. The $51.8 million difference between the gross proceeds received from issuance of the Convertible Notes of $230.0 million and the estimated fair value of the liability component represents the equity component, or the “Conversion Option”, of the Convertible Notes and was recorded in additional paid-in capital. The equity component is not remeasured as long as it continues to meet the conditions for equity classification.

The Company allocated issuance costs related to the issuance of the Convertible Notes to the liability and equity components using the same proportions as the initial carrying value of the Convertible Notes. Issuance costs attributable to the liability component were $6.3 million and are being amortized to interest expense using the effective interest method over the term of the Convertible Notes. Issuance costs attributable to the equity components were $1.8 million and are netted with the equity component of the Convertible Notes in stockholders’ equity on the condensed consolidated balance sheets.

The net carrying value of the liability component of the Convertible Notes was as follows (in thousands):

	December 31,
	2019
Principal	$	230,000
Less: unamortized debt discount		46,820
Less: unamortized debt issuance costs		5,686
Net carrying amount	$	177,494

The net carrying value of the equity component of the Convertible Notes was as follows (in thousands):

	December 31,
	2019
Proceeds allocated to the conversion option (debt discount)	$	51,842
Less: issuance costs		1,833
Net carrying amount	$	50,009

The interest expense related to the Convertible Notes was as follows (in thousands):

	For the Year Ended December 31,
	2019
Contractual interest expense	$	313
Amortization of debt issuance cost and discount		5,635
Total	$	5,948

Credit agreement

Revolving credit facility

The Company has a $150.0 million credit agreement that was amended on June 5, 2019, to permit the issuance of the Convertible Notes and extend the maturity date of the credit facility to December 15, 2023 (“2019 Amended Credit Agreement”). The 2019 Amended Credit Agreement provides for an accordion feature that allows the Company to expand the size of the revolving line of credit by an additional $50.0 million, subject to certain conditions, by obtaining additional commitments from the existing lenders or by causing a person acceptable to the administrative agent to become a lender (in each case subject to the terms and conditions set forth in the 2019 Amended Credit Agreement).

As of December 31, 2019, the Company had no outstanding borrowings under the 2019 Amended Credit Agreement and there was $150.0 million available for future borrowing. The 2019 Amended Credit Agreement is available for general corporate purposes, including working capital, capital expenditures, and permitted acquisitions.

Borrowings under the 2019 Amended Credit Agreement bear interest at a rate per annum equal to an agreed upon applicable margin plus, at the Company’s option, either the Alternate Base Rate (defined as the greatest of (1) the Prime Rate (as defined in the 2019 Amended Credit Agreement) in effect on such day, (2) the Federal Funds Effective Rate (as defined in the 2019 Amended Credit Agreement) in effect on such day plus 1/2 of 1.00% or (3) the Adjusted LIBO Rate (as defined in the 2019 Amended Credit Agreement) for a one month interest period on such day (or if such day is not a business day, the immediately preceding business day) plus 1.00%) or the Adjusted LIBO Rate. The applicable margin for borrowings under the 2019 Amended Credit Agreement is based on the Company’s most recently tested consolidated total net leverage ratio and will vary from (a) in the case of Eurodollar loans, 1.25% to 2.00%, and (b) in the case of ABR loans or swingline loans, 0.25% to 1.00%. The Company pays a commitment fee ranging from 0.15% to 0.30% on the unused portion of the 2019 Amended Credit Agreement. The weighted average interest rate on borrowings under the 2019 Amended Credit Agreement was 3.6% for the year ended December 31, 2019.

Collateral and guarantees

The 2019 Amended Credit Agreement is secured by collateral including (i) substantially all of the Company’s properties and assets, and the properties and assets of the Company’s domestic subsidiaries but excluding any patents, copyrights, patent applications or copyright applications or any trade secrets or software products and (ii) pledges of the equity interests in all present and future domestic subsidiaries (subject to certain exceptions as provided for under the 2019 Amended Credit Agreement). The Company’s direct and indirect domestic subsidiaries are guarantors of all the obligations under the 2019 Amended Credit Agreement.

Debt covenants

The 2019 Amended Credit Agreement requires the Company to maintain the following financial covenants:

•

Maximum Net Leverage Ratio : On the last day of each fiscal quarter, the Company on a consolidated basis will not permit the ratio of total indebtedness (net of unrestricted domestic cash in excess of $20.0 million) to EBITDA, as such terms are defined in the 2019 Amended Credit Agreement, for the rolling four quarter period ending on such date to be greater than 5.00 to 1.00 as of the last day of each fiscal quarter.

•

Senior Secured Leverage Ratio : On the last day of each fiscal quarter, the Company on a consolidated basis will not permit the ratio of total indebtedness secured by a lien (net of unrestricted domestic cash in excess of $20.0 million) to EBITDA, as such terms are defined in the 2019 Amended Credit Agreement, for the rolling four quarter period ending on such date to be greater than 3.00 to 1.00 as of the last day of each fiscal quarter.

•

Consolidated Interest Coverage Ratio : On the last day of each fiscal quarter, the Company on a consolidated basis will not permit the ratio of (x) EBITDA to (y) cash Consolidated Interest Expense, as such terms are defined in the 2019 Amended Credit Agreement, in each case for the rolling four quarter period ending on such date, to be less than 3.00 to 1.00 as of the last day of each fiscal quarter.

At December 31, 2019, the Company was in compliance with all of the above financial covenants.

Other

The Company has available overdraft and line of credit facilities in several countries in which it operates. These credit facilities are with various domestic and international banks and are at quoted market rates. At both December 31, 2019 and 2018, the Company had $3.5 million of availability under these facilities and there were no outstanding commitments.

Retirement Benefits

12 Months Ended

Dec. 31, 2019

Compensation And Retirement Disclosure [Abstract]

Retirement Benefits

16. Retirement benefits

The Company sponsors a 401(k)-profit sharing plan (the “Plan”) for all eligible U.S. employees. This Plan allows eligible employees to contribute up to 80% of their compensation to the Plan. The Company makes discretionary matching contributions to the Plan provided the employee is employed on the last day of the year. Such discretionary contributions vest ratably over five years of service. The Company’s contributions to the Plan were $1.6 million, $1.3 million and $1.1 million for the years ended December 31, 2019, 2018 and 2017, respectively.

The Company also participates in government-mandated retirement and/or termination indemnity plans, benefiting certain non-U.S. employees. Termination benefits are generally lump sum payments based upon an individual’s years of credited service and annual salary at retirement. These plans are generally unfunded, and employees receive payments at the time of retirement or termination under applicable labor laws or agreements. The amount of net benefit cost recorded in the consolidated statements of operations for these plans was $1.8 million, $1.2 million and $1.2 million in 2019, 2018 and 2017, respectively. The amount of benefits paid under these plans was $0.4 million, $0.4 million and $0.2 million in 2019, 2018 and 2017, respectively. The accumulated benefit obligation, unlike the projected benefit obligation, does not reflect expected benefit increases from future salary levels, and was $6.8 million and $6.0 million at December 31, 2019 and 2018, respectively, under these plans. The projected benefit obligation, net of plan assets of $0.9 million, was $11.0 million and $9.6 million at December 31, 2019 and 2018, respectively.

A summary of the components of the pension benefits obligation recorded in the consolidated balance sheets are as follows (in thousands):

	December 31,
	2019		2018
Accrued compensation and benefits	$	596	$	513
Other long-term liabilities		10,379		9,111
	$	10,975	$	9,624

The estimated future benefit payments, which reflect expected future service, that are expected to be paid for each of the next five years are as follows (in thousands):

Year ending
December 31, 2020	$	617
December 31, 2021	$	292
December 31, 2022	$	347
December 31, 2023	$	519
December 31, 2024	$	431
Next five years	$	2,991

Goodwill and Other Intangible Assets

12 Months Ended

Dec. 31, 2019

Goodwill And Intangible Assets Disclosure [Abstract]

Goodwill and Other Intangible Assets

6. Goodwill and other intangible assets

Goodwill

The changes in the carrying amount of goodwill, which is attributable to the Software reportable segment, are as follows (in thousands):

Balance at December 31, 2017	$	62,706
Acquisitions		152,630
Effects of foreign currency translation and other		(4,804	)
Balance at December 31, 2018		210,532
Acquisitions		21,922
Effects of foreign currency translation and other		1,229
Balance at December 31, 2019	$	233,683

Other intangible assets

A summary of other intangible assets is shown below (in thousands):

	December 31, 2019
	Weighted average amortization period	Gross carrying amount		Accumulated amortization		Net carrying amount
Definite-lived intangible assets:
Developed technology	4-6 years	$	60,916	$	25,838	$	35,078
Customer relationships	7-10 years		32,582		11,575		21,007
Other intangibles	10 years		111		62		49
Total definite-lived intangible assets			93,609		37,475		56,134
Indefinite-lived intangible assets:
Trade names			10,941				10,941
Total other intangible assets		$	104,550	$	37,475	$	67,075

	December 31, 2018
	Weighted average amortization period	Gross carrying amount		Accumulated amortization		Net carrying amount
Definite-lived intangible assets:
Developed technology	4-6 years	$	54,530	$	15,517	$	39,013
Customer relationships	7-10 years		28,422		7,309		21,113
Other intangibles	10 years		109		56		53
Total definite-lived intangible assets			83,061		22,882		60,179
Indefinite-lived intangible assets:
Trade names			9,657				9,657
Total other intangible assets		$	92,718	$	22,882	$	69,836

Amortization expense related to amortizing intangible assets was $14.4 million, $7.7 million and $5.4 million for the years ended December 31, 2019, 2018 and 2017, respectively.

Estimated amortization expense for the next five years as of December 31, 2019 is as follows (in thousands):

Year ending
December 31, 2020	$	15,004
December 31, 2021	$	12,664
December 31, 2022	$	9,466
December 31, 2023	$	8,276
December 31, 2024	$	6,490
Thereafter	$	4,234
Total	$	56,134

Stockholders’ Equity

12 Months Ended

Dec. 31, 2019

Equity [Abstract]

Stockholders' Equity

12. Stockholders’ equity

Preferred stock

As of December 31, 2019, the Company had authorized 45,000,000 shares of preferred stock, par value $0.0001, of which no shares were issued or outstanding. The Board of Directors has the authority to issue the preferred stock in one or more series and to fix rights, preferences, privileges, and restrictions, including dividends and the number of shares constituting any series or the designation of such series, without any further vote or action by the stockholders.

Common stock

As of December 31, 2019, the Company had authorized 513,796,572 shares of Class A common stock, par value $0.0001, and 41,203,428 shares of Class B common stock, par value $0.0001. The rights of the holders of Class A common stock and Class B

common stock are identical, except with respect to voting and conversion rights. Each share of Class A common stock is entitled to one vote per share. Each share of Class B common stock is entitled to ten votes per share and is convertible into one share of Class A common stock.

The holders of Class A and Class B common stock are entitled to dividends at the sole discretion of the Board of Directors. No common stock dividends were declared or paid in 2019, 2018, or 2017.

Consolidated statements of operations - USD ($)
shares in Thousands, $ in Thousands

12 Months Ended

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

^[1]

$ 458,915

$ 396,379

$ 333,333

132,599

115,973

106,591

326,316

280,406

226,742

Research and development

117,510

97,592

93,234

General and administrative

106,051

80,277

79,958

82,178

79,751

87,979

Amortization of intangible assets

14,442

7,739

5,448

Other operating income

(2,072)

(9,597)

(6,620)

318,109

255,762

259,999

Other (income) expense, net

8,207

24,644

(33,257)

Interest expense

6,371

200

2,160

(1,552)

(2,580)

994

3,388

27,024

(36,411)

10,930

11,489

65,530

Net (loss) income per share attributable to common stockholders, basic

$ (7,542)

$ 15,535

$ (101,941)

(Loss) income per share:

$ (0.11)

$ 0.23

$ (1.94)

Net (loss) income per share attributable to common stockholders, diluted

$ (0.11)

$ 0.21

$ (1.94)

Weighted average shares outstanding:

Weighted average number of shares used in computing net (loss) income per share, basic

71,544

67,468

52,466

Weighted average number of shares used in computing net (loss) income per share, diluted

71,544

74,878

52,466

License [Member]

$ 244,321

$ 207,164

Maintenance and Other Services [Member]

21,285

16,119

122,381

97,197

38,401

29,655

Total Software [Member]

366,702

304,361

$ 244,817

Software Related Services [Member]

59,686

45,774

36,360

34,576

36,945

35,397

Total Software and Related Services [Member]

25,640

26,415

26,888

401,278

341,306

280,214

Client Engineering Services [Member]

85,326

72,189

63,248

48,987

47,852

46,510

39,875

38,979

38,131

Other [Member]

8,650

7,221

6,609

$ 7,398

$ 4,805

$ 5,212

[1]	The year ended December 31, 2017 has been reported under ASC 605 and has not been adjusted under the modified retrospective approach of ASC 606. See Note 3 – Revenue from contracts with customers for the effect of the adoption of ASC 606 on the Company’s consolidated financial statements.

Revenue from Contracts with Customers - Schedule of Disaggregation of Revenue (Detail) - USD ($)
$ in Thousands

3 Months Ended

12 Months Ended

Dec. 31, 2019

Sep. 30, 2019

Jun. 30, 2019

Mar. 31, 2019

Dec. 31, 2018

Sep. 30, 2018

Jun. 30, 2018

Mar. 31, 2018

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

^[1]

$ 123,877

$ 100,406

$ 106,773

$ 127,859

$ 103,011

$ 86,751

$ 93,360

$ 113,257

$ 458,915

$ 396,379

$ 333,333

Term Licenses [Member]

Perpetual Licenses [Member]

201,881

168,909

42,440

38,255

Maintenance [Member]

Professional Services and Other [Member]

103,699

86,150

18,682

11,047

Software [Member]

Quarterly Financial Information Disclosure [Abstract]

$ 366,702

$ 304,361

$ 244,817

[1]	The year ended December 31, 2017 has been reported under ASC 605 and has not been adjusted under the modified retrospective approach of ASC 606. See Note 3 – Revenue from contracts with customers for the effect of the adoption of ASC 606 on the Company’s consolidated financial statements.

Supplemental Quarterly Financial Information (Unaudited) - Summary of Quarterly Financial Information (Detail) - USD ($)
$ / shares in Units, $ in Thousands

3 Months Ended

12 Months Ended

Dec. 31, 2019

Sep. 30, 2019

Jun. 30, 2019

Mar. 31, 2019

Dec. 31, 2018

Sep. 30, 2018

Jun. 30, 2018

Mar. 31, 2018

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

^[1]

$ 123,877

$ 100,406

$ 106,773

$ 127,859

$ 103,011

$ 86,751

$ 93,360

$ 113,257

$ 458,915

$ 396,379

$ 333,333

86,927

68,665

75,750

94,974

72,740

59,547

63,904

84,215

326,316

280,406

226,742

4,149

(10,507)

(3,202)

17,767

(3,557)

1,880

175

26,146

8,207

24,644

(33,257)

Net income (loss) per share, basic

$ (1,502)

$ (15,939)

$ (3,120)

$ 13,019

$ (9,003)

$ 934

$ (1,080)

$ 24,684

$ (7,542)

$ 15,535

$ (101,941)

$ (0.02)

$ (0.22)

$ (0.04)

$ 0.18

$ (0.13)

$ 0.01

$ (0.02)

$ 0.39

$ (0.11)

$ 0.23

$ (1.94)

Net income (loss) per share, diluted

$ (0.02)

$ (0.22)

$ (0.04)

$ 0.17

$ (0.13)

$ 0.01

$ (0.02)

$ 0.34

$ (0.11)

$ 0.21

$ (1.94)

[1]	The year ended December 31, 2017 has been reported under ASC 605 and has not been adjusted under the modified retrospective approach of ASC 606. See Note 3 – Revenue from contracts with customers for the effect of the adoption of ASC 606 on the Company’s consolidated financial statements.

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

Other Liabilities Disclosure [Abstract]

Debt - Schedule of Interest Expense Related to Convertible Notes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Amortization of debt issuance cost and discount	$ 5,663	$ 23	$ 148
Convertible Senior Notes Due in 2024 [Member]
Debt Instrument [Line Items]
Contractual interest expense	313
Amortization of debt issuance cost and discount	5,635
Total	$ 5,948

Goodwill and Other Intangible Assets - Summary of Estimated Amortization Expense (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
December 31, 2020	$ 15,004
December 31, 2021	12,664
December 31, 2022	9,466
December 31, 2023	8,276
December 31, 2024	6,490
Thereafter	4,234
Net carrying amount	$ 56,134	$ 60,179

Other Liabilities

12 Months Ended

Dec. 31, 2019

Other Liabilities

9. Other liabilities

The following table provides the details of other accrued expenses and current liabilities (in thousands):

	December 31,
	2019		2018
Income taxes payable	$	6,008	$	3,932
Accrued VAT		5,312		4,536
Accrued professional fees		2,581		3,165
Accrued royalties		2,314		2,613
Defined contribution plan liabilities		1,593		1,376
Obligations for acquisition of businesses		1,362		1,218
Non-income tax liabilities		1,253		853
Billings in excess of cost		879		1,504
Other current liabilities		7,301		7,842
Total	$	28,603	$	27,039

The following table provides the details of other long-term liabilities (in thousands):

	December 31,
	2019		2018
Pension and other post retirement liabilities	$	10,379	$	9,111
Deferred tax liabilities		6,275		5,339
Other liabilities		10,018		11,306
Total	$	26,672	$	25,756

Acquisitions and Disposals - Additional Information (Detail) - USD ($)					1 Months Ended	12 Months Ended
	Oct. 31, 2022	Nov. 07, 2019	Dec. 13, 2018	Oct. 31, 2018	Oct. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Oct. 05, 2017
Business Acquisition [Line Items]
Business acquisition, par value of shares issued									$ 0.0001
Goodwill						$ 233,683,000	$ 210,532,000	$ 62,706,000
Business combination, consideration transferred, outstanding equity award						7,637,000	$ 8,681,000	$ 8,712,000
Business combination, pre-combination expense and consideration transferred						$ 600,000
Class A Common Stock [Member]
Business Acquisition [Line Items]
Business acquisition, par value of shares issued						$ 0.0001	$ 0.0001
Polliwog Co. Ltd. [Member]
Business Acquisition [Line Items]
Land and building					$ 2,900,000
Goodwill					15,400,000
Polliwog Co. Ltd. [Member] \| Tradenames [Member]
Business Acquisition [Line Items]
Finite-lived intangibles					500,000
Polliwog Co. Ltd. [Member] \| Customer Relationships [Member]
Business Acquisition [Line Items]
Finite-lived intangibles					500,000
Polliwog Co. Ltd. [Member] \| Developed Technology [Member]
Business Acquisition [Line Items]
Finite-lived intangibles					$ 400,000
Polliwog Co. Ltd. [Member] \| Stock Purchase Agreement [Member]
Business Acquisition [Line Items]
Business acquisition, percentage of interest acquired					97.00%
Fair value of consideration transferred					$ 19,300,000
Payments of outstanding debt					$ 2,200,000
Polliwog Co. Ltd. [Member] \| Second Stock Purchase Agreement [Member] \| Scenario Forecast [Member]
Business Acquisition [Line Items]
Business acquisition, percentage of interest acquired	3.00%
Fair value of consideration transferred	$ 800,000
Polliwog Co. Ltd. [Member] \| Class A Common Stock [Member]
Business Acquisition [Line Items]
Business acquisition, shares issued					256,594
Business acquisition, equity interest issued or issuable, description					Stock Purchase Agreement, 256,594 shares of the Company’s Class A Common Stock will be issued to existing employees, subject to continuing employment. The shares will be issued on the one-, two- and three-year anniversaries of the closing
Polliwog Co. Ltd. [Member] \| Class A Common Stock [Member] \| Stock Purchase Agreement [Member]
Business Acquisition [Line Items]
Business acquisition, consideration					$ 10,700,000
Business acquisition, shares issued					199,360
Business acquisition, par value of shares issued					$ 0.0001
Business acquisition, equity interest issued or issuable, description					SPA Stock Consideration will be issuable in installments of 88,323 shares on the first anniversary of the closing and 91,908 shares on the second and third year anniversaries of the closing
Business acquisition, shares not yet recognized as stock-based compensation					256,594
Polliwog Co. Ltd. [Member] \| Class A Common Stock [Member] \| Stock Purchase Agreement [Member] \| Customary Securities Law Restrictions on Transferability [Member]
Business Acquisition [Line Items]
Business acquisition, shares issued					183,815
Polliwog Co. Ltd. [Member] \| Class A Common Stock [Member] \| Stock Purchase Agreement [Member] \| Potential reduction and Customary Securities Law Restrictions on Transferability [Member]
Business Acquisition [Line Items]
Business acquisition, shares issued					15,545
Polliwog Co. Ltd. [Member] \| Class A Common Stock [Member] \| Second Stock Purchase Agreement [Member] \| Scenario Forecast [Member]
Business Acquisition [Line Items]
Business acquisition, additional consideration paid in cash	$ 300,000
Business acquisition, number of additional shares issued	14,213
DEM Solutions Limited [Member]
Business Acquisition [Line Items]
Goodwill		$ 5,600,000
DEM Solutions Limited [Member] \| Tradenames [Member]
Business Acquisition [Line Items]
Finite-lived intangibles		600,000
DEM Solutions Limited [Member] \| Customer Relationships [Member]
Business Acquisition [Line Items]
Finite-lived intangibles		3,100,000
DEM Solutions Limited [Member] \| Developed Technology [Member]
Business Acquisition [Line Items]
Finite-lived intangibles		$ 3,700,000
DEM Solutions Limited [Member] \| Stock Purchase Agreement [Member]
Business Acquisition [Line Items]
Business acquisition, percentage of interest acquired		100.00%
Fair value of consideration transferred		$ 13,100,000
Datawatch Corporation [Member]
Business Acquisition [Line Items]
Fair value of consideration transferred			$ 183,427,000
Business acquisition, consideration						$ 183,400,000
Payments of outstanding debt						$ 8,000,000.0
Land and building			980,000
Goodwill			$ 131,593,000
Business acquisition purchase price			$ 13.10			$ 13.10
Business combination, consideration transferred value						$ 168,200,000
Business combination, consideration transferred, liabilities incurred						500,000
Business combination, consideration transferred for outstanding equity awards						6,700,000
Business Acquisition, Transaction Costs							$ 10,400,000
Business combination, pre-combination expense and consideration transferred			$ 500,000
Business combination, consideration allocated to future services			3,400,000
Fair value of assets acquired and liabilities assumed			$ 51,834,000
Datawatch Corporation [Member] \| Restricted Stock Units (RSUs) [Member]
Business Acquisition [Line Items]
Business acquisition purchase price			$ 13.10
Business combination, consideration transferred value			$ 3,900,000
Business combination, consideration transferred, outstanding equity award			6,700,000
Datawatch Corporation [Member] \| Customer Relationships [Member]
Business Acquisition [Line Items]
Finite-lived intangibles			16,700,000
Datawatch Corporation [Member] \| Developed Technology [Member]
Business Acquisition [Line Items]
Finite-lived intangibles			$ 22,600,000
SIMSOLID Corporation [Member]
Business Acquisition [Line Items]
Fair value of consideration transferred				$ 22,100,000
Fair value of assets acquired and liabilities assumed						$ 0

Commitments and Contingencies

12 Months Ended

Dec. 31, 2019

Commitments And Contingencies Disclosure [Abstract]

Commitments and Contingencies

18. Commitments and contingencies

Swedish Tax Litigation

The Swedish Tax Authorities, or STA, have assessed tax, penalties and interest in the amount of $6.5 million related to the acquisition of Panopticon AB by Datawatch, in 2013 for the years 2013, 2014 and 2015. The STA, upon auditing the acquisition transaction, reached a conclusion that post acquisition, certain assets were transferred from Sweden, triggering the tax obligation. The STA is also of the opinion that some services related to product development provided to the new parent company in the U.S. were performed by Panopticon AB at a price below market price triggering tax obligations. Datawatch contested the findings by the STA throughout the audit process including contesting the STA position in the first level of administrative courts. An Administrative Court hearing was held on May 16, 2019. On May 29, 2019, the Administrative Court issued its ruling in favor of Datawatch AB. On July 4, 2019, the STA filed an appeal of the Administrative Court ruling with the Administrative Court of Appeal, or the Court of Appeals, in Stockholm, effectively continuing to assert that the assessments are in fact appropriate. In late September 2019, the Company submitted its filing in response to the STA appeal with the Court of Appeals. On October 10, 2019, the STA filed an answer to the Company’s defrayment, and on January 31, 2020, the Company filed a second submission to the Court. The Court of Appeals held a hearing regarding this matter on February 20, 2020. The Company continues to contest the assessment through the appeals process and no rulings have been issued by the Court of Appeals relative to the claims of the STA and the Company’s response as of this point. The Company has determined that these events do not cause a change in the assessment of uncertain tax positions.

Potential Export Violation

As previously disclosed, on May 10, 2019, the Company discovered potential violations of U.S. economic sanctions and export control laws and immediately filed preliminary self-disclosure notices with the U.S. Treasury Department’s Office of Foreign Assets Control (“OFAC”) and the U.S. Commerce Department’s Bureau of Industry & Security (“BIS”).

The Company subsequently conducted an internal investigation into these issues under the direction of outside legal counsel and filed voluntary self-disclosures with both agencies on July 25, 2019. These disclosures describe the unintentional transfer of commercial software and trial software licenses to various individuals located in Iran and other restricted countries. These transfers involved freeware, trial software licenses, and volunteer software testing communities. The Company did not discover any evidence indicating any commercial transactions with restricted parties or countries.

In addition to filing voluntary self-disclosures with OFAC and BIS, the Company has implemented a series of additional compliance measures to prevent unintentional transfers of the sort described above. These measures will further enhance the Company’s international trade compliance program, which is designed to assure that the Company does not conduct business directly or indirectly with any countries or parties subject to U.S. economic sanctions and export control laws.

On August 30, 2019, BIS notified the Company that it had completed its investigation of the potential violation of U.S. export control laws by the Company and concluded that no criminal or administrative prosecution was warranted and closed the matter.

On January 10, 2020, OFAC issued a Cautionary Letter to the Company stating that it had completed its investigation of the potential violation of U.S. export control laws by the Company and concluded that no criminal or administrative prosecution or fines were warranted and closed the matter.

Legal proceedings

From time to time, the Company may be subject to legal proceedings and claims in the ordinary course of business. The Company has received, and may in the future continue to receive, claims from third parties asserting, among other things, infringement of their intellectual property rights. Future litigation may be necessary to defend the Company, its partners and its customers by determining the scope, enforceability and validity of third party proprietary rights, or to establish and enforce the Company’s proprietary rights. The results of any current or future litigation cannot be predicted with certainty and regardless of the outcome, litigation can have an adverse impact on the Company because of defense and settlement costs, diversion of management resources and other factors.

Royalty agreements

The Company has entered into various renewable, nonexclusive license agreements under which the Company has been granted access to the licensor’s technology and the right to sell or use the technology in the Company’s products. Royalties are payable to developers of the software at various rates and amounts, which generally are based upon unit sales or revenue. Royalty fees were $10.6 million, $9.7 million, and $9.3 million for the years ended December 31, 2019, 2018 and 2017, respectively, and are reported in Cost of revenue—software and Cost of revenue—other.

Consolidated statements of cash flows - USD ($)	12 Months Ended
Consolidated statements of cash flows - USD ($)	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
OPERATING ACTIVITIES:
Net (loss) income	$ (7,542,000)	$ 15,535,000	$ (101,941,000)
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Depreciation and amortization	21,522,000	14,734,000	11,747,000
Provision for bad debt	671,000	394,000	610,000
Amortization of debt discount and issuance costs	5,663,000	23,000	148,000
Stock-based compensation expense	8,528,000	3,339,000	47,281,000
Loss (gain) on sale of assets held for sale and other	6,000	(4,503,000)	(244,000)
Impairment of intangible assets	0	608,000
Deferred income taxes	(950,000)	(1,057,000)	55,105,000
Other, net		(206,000)	394,000
Changes in assets and liabilities:
Accounts receivable	(7,901,000)	(1,394,000)	(10,397,000)
Prepaid expenses and other current assets	(2,396,000)	204,000	1,559,000
Other long-term assets	(2,591,000)	(1,660,000)	(11,288,000)
Accounts payable	(426,000)	1,647,000	(1,087,000)
Accrued compensation and benefits	(1,232,000)	5,678,000	2,060,000
Other accrued expenses and current liabilities	513,000	(6,667,000)	6,207,000
Operating lease right of use assets and liabilities, net	102,000
Deferred revenue	17,426,000	9,555,000	15,937,000
Net cash provided by operating activities	31,393,000	36,230,000	16,091,000
INVESTING ACTIVITIES:
Payments for acquisition of businesses, net of cash acquired	(25,720,000)	(203,438,000)	(15,582,000)
Capital expenditures	(9,660,000)	(6,659,000)	(7,522,000)
Proceeds from sale of assets held for sale and other		6,614,000	446,000
Payments for acquisition of developed technology	(473,000)	(2,727,000)	(2,120,000)
Other investing activities, net	14,000		(73,000)
Net cash used in investing activities	(35,839,000)	(206,210,000)	(24,851,000)
FINANCING ACTIVITIES:
Proceeds from issuance of convertible senior notes, net of underwriters' discounts and commissions	223,101,000
Proceeds from issuance of Class A common stock in follow-on public offering, net of underwriters' discounts and commissions		135,572,000
Borrowings under revolving commitment	96,992,000	37,041,000	126,832,000
Payments on revolving commitment	(127,941,000)	(6,091,000)	(154,187,000)
Proceeds from issuance of common stock	1,510,000	2,077,000	1,792,000
Payments for issuance costs of convertible senior notes	(1,233,000)
Payments for follow-on public offering and IPO offering costs		(556,000)	(4,644,000)
Principal payments on long-term debt		(126,000)	(59,869,000)
Payments for redemption of common stock		(119,000)	(1,045,000)
Proceeds from issuance of Class A common stock in initial public offering, net of underwriters' commissions			119,268,000
Proceeds from issuance of debt			1,541,000
Other financing activities	(513,000)	(268,000)	(130,000)
Net cash provided by financing activities	191,916,000	167,530,000	29,558,000
Effect of exchange rate changes on cash, cash equivalents and restricted cash	342,000	(1,443,000)	1,641,000
Net increase (decrease) in cash, cash equivalents and restricted cash	187,812,000	(3,893,000)	22,439,000
Cash, cash equivalents and restricted cash at beginning of year	35,685,000	39,578,000	17,139,000
Cash, cash equivalents and restricted cash at end of period	223,497,000	35,685,000	39,578,000
Supplemental disclosures of cash flow:
Interest paid	664,000	223,000	2,092,000
Income taxes paid	7,686,000	6,735,000	5,893,000
Supplemental disclosure of non-cash investing and financing activities:
Issuance of common stock in connection with acquisitions	7,637,000	8,681,000	8,712,000
Promissory notes issued and deferred payment obligations for acquisitions	497,000	1,729,000	12,352,000
Finance leases	632,000	895,000	124,000
Property and equipment in accounts payable, other accrued expenses and current liabilities, and other liabilities	$ 259,000	$ 330,000	582,000
Issuance of common stock with put rights			2,352,000
Initial public offering costs in accounts payable			$ 186,000

Accumulated Other Comprehensive Loss - Components of Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	$ 293,686	$ 58,948	$ (33,762)
Other comprehensive income (loss) before reclassification	1,957	(5,359)	2,138
Amounts reclassified from accumulated other comprehensive loss	(179)	(1,177)	54
Tax effects	(16)	318
Total other comprehensive (loss) income	1,762	(6,218)	2,192
Ending balance	354,707	293,686	58,948
Foreign Currency Translation [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(8,823)	(3,374)	(5,725)
Other comprehensive income (loss) before reclassification	1,895	(5,449)	2,351
Total other comprehensive (loss) income	1,895	(5,449)	2,351
Ending balance	(6,928)	(8,823)	(3,374)
Retirement Related Benefit Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(2,467)	(1,698)	(1,539)
Other comprehensive income (loss) before reclassification	62	90	(213)
Amounts reclassified from accumulated other comprehensive loss	(179)	(1,177)	54
Tax effects	(16)	318
Total other comprehensive (loss) income	(133)	(769)	(159)
Ending balance	(2,600)	(2,467)	(1,698)
Accumulated Other Comprehensive Loss [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(11,290)	(5,072)	(7,264)
Ending balance	$ (9,528)	$ (11,290)	$ (5,072)

Description of Business

12 Months Ended

Dec. 31, 2019

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Description of Business

1. Description of business

Altair Engineering Inc. (“Altair” or the “Company”) incorporated in the state of Michigan in 1985 and became a Delaware corporation in October 2017. The Company is a global technology company providing software and cloud solutions in the areas of product design and development, high performance computing and data analytics. Altair enables organizations across broad industry segments to compete more effectively in a connected world while creating a more sustainable future. The Company is based in Troy, Michigan.

The Company’s simulation-driven approach to innovation is powered by the Company’s broad portfolio of high-fidelity and high-performance physics solvers. The Company’s integrated suite of software optimizes design performance across multiple disciplines encompassing structures, motion, fluids, thermal management, electromagnetics, system modeling, and embedded systems, while also providing data analytics and true-to-life visualization and rendering.

Altair’s software products represent a comprehensive, open architecture solution for simulation, data analytics and cloud computing to empower decision making for improved product development, manufacturing, energy management and exploration, financial services, health care, and retail operations. Altair believes its products offer a comprehensive set of technologies to design and optimize high performance, efficient, innovative and sustainable products and processes in an increasingly connected world.

Altair also provides Client Engineering Services to support its customers with long-term ongoing product design and development expertise. This has the benefit of embedding the Company within customers, deepening its understanding of their processes, and allowing the Company to more quickly perceive trends in the overall market, helping the Company to better tailor its research and development and sales initiatives. The Company hires engineers and data scientists for placement at a customer site for specific customer-directed assignments.

Initial public offering

In November 2017, the Company closed its initial public offering (“IPO”), in which the Company issued and sold 9,865,004 shares of Class A common stock inclusive of the underwriters’ option to purchase additional shares that was exercised in full. The price per share to the public was $13.00. The Company received aggregate proceeds of $119.3 million from the IPO, net of underwriters’ discounts and commissions, before deducting offering costs of approximately $4.8 million.

The IPO also included the sale of 3,934,996 shares of Class A common stock by certain stockholders, giving effect to the conversion of 2,200,000 shares of the Company’s Class B common stock into an equivalent number of shares of Class A common stock, and 1,734,996 stock options for Class A common stock exercised by the Company’s chief executive officer. The Company did not receive any proceeds from the sale of shares of Class A common stock by the selling stockholders.

Follow-on public offering

In June 2018, the Company closed its follow-on public offering (the “Offering”), in which the Company issued and sold 4,056,004 shares of Class A common stock (inclusive of 763,424 shares sold upon the exercise by the underwriters of their option to purchase additional shares of our Class A common stock). The price per share to the public was $35.00. The Company received aggregate proceeds of $135.6 million from the Offering, net of underwriters’ discounts and commissions, before deducting offering costs of approximately $0.4 million.

The Offering also included the sale of 2,307,420 shares of Class A common stock by selling stockholders, giving effect to the conversion of 1,675,420 shares of the Company’s Class B common stock into an equivalent number of shares of Class A common stock and the exercise of 257,000 options to purchase Class A common stock. The Company did not receive any proceeds from the sale of shares of Class A common stock by the selling stockholders other than the $0.5 million in proceeds from exercises of stock options by certain selling stockholders.

Revenue from Contracts with Customers - Additional Information (Detail)1	Dec. 31, 2019
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2020-01-01
Revenue From Contracts With Customers [Line Items]
Revenue, remaining contractual obligation, expected to recognize, period	12 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2021-01-01
Revenue From Contracts With Customers [Line Items]
Revenue, remaining contractual obligation, expected to recognize, period	24 months

Stock-based Compensation - Summary of Fair value of Company's Stock Options Granted (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant date fair value per share	$ 38.11
Expected volatility	42.00%	34.00%
Expected term (in years)	6 years 3 months
Risk-free interest rate	1.80%	2.02%
Expected dividend yield	0.00%	0.00%
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant date fair value per share		$ 1.86
Expected term (in years)		5 years 9 months
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant date fair value per share		$ 1.94
Expected term (in years)		6 years 3 months

Segment Information (Tables)

12 Months Ended

Dec. 31, 2019

Segment Reporting [Abstract]

Schedule of Segment Reporting Information

The following tables are in thousands:

Year ended December 31, 2019	Software		CES		All other			Total
Revenue	$	401,278	$	48,987	$	8,650		$	458,915
Adjusted EBITDA	$	38,834	$	5,255	$	(4,540	)	$	39,549

Year ended December 31, 2018	Software		CES		All other			Total
Revenue	$	341,306	$	47,852	$	7,221		$	396,379
Adjusted EBITDA	$	48,643	$	5,155	$	(3,618	)	$	50,180

Year ended December 31, 2017	Software		CES		All other			Total
Revenue	$	280,214	$	46,510	$	6,609		$	333,333
Adjusted EBITDA	$	22,864	$	4,966	$	(5,313	)	$	22,517

Reconciliation of U.S. GAAP Income (Loss) Before Income Taxes to Adjusted EBITDA

	Year ended December 31,
	2019			2018			2017
Reconciliation of Adjusted EBITDA to GAAP income (loss) before income taxes:
Adjusted EBITDA	$	39,549		$	50,180		$	22,517
Stock-based compensation expense		(8,528	)		(3,339	)		(47,281	)
Interest expense		(6,371	)		(200	)		(2,160	)
Interest income and other⁽¹⁾		260			(4,883	)		2,260
Depreciation and amortization		(21,522	)		(14,734	)		(11,747	)
Income (loss) before income taxes	$	3,388		$	27,024		$	(36,411	)

⁽¹⁾

^{Includes for the year ended December 31, 2019 a) nonrecurring acquisition related costs of $0.6 million, b) nonrecurring severance expense of $0.4 million, and c) impairment charges for royalty contracts of $1.0 million of expense. Includes for the year ended December 31, 2018 a) nonrecurring costs from the acquisition of Datawatch of $10.4 million, b) gain on the sale of a building of $4.4 million, and c) impairment charges for royalty contracts and trade names of $2.8 million of expense. Includes for each of the years ended December 31, 2018 and 2017, a non-recurring adjustment for a change in estimated legal expenses of $2.0 million of income in each year.}

Summary of Sales to External Customers and Long-Lived Assets by Geographical Areas

Revenue is attributed to geographic areas based on the country of origin. The following table provides sales to external customers and long-lived assets for each of the geographic areas in which the Company operates (in thousands):

	Revenue						Long-lived assets (1)
	Year ended December 31,						December 31,
	2019		2018		2017		2019		2018
United States	$	219,053	$	186,026	$	142,679	$	55,319	$	63,266
Other countries		14,753		8,604		6,404		10,190		11,447
Total Americas		233,806		194,630		149,083		65,509		74,713
Germany		50,102		45,664		43,751		3,405		4,305
France		17,210		16,154		18,128		1,224		1,583
Other countries		49,312		42,846		40,050		11,316		4,729
Total Europe, Middle East and Africa		116,624		104,664		101,929		15,945		10,617
Japan		37,757		35,478		33,686		2,036		2,045
Other countries		70,728		61,607		48,635		8,941		2,957
Total Asia Pacific		108,485		97,085		82,321		10,977		5,002
Total	$	458,915	$	396,379	$	333,333	$	92,431	$	90,332

(1)	Includes property and equipment, net and definite-lived intangible assets, net.

Segment Information

12 Months Ended

Dec. 31, 2019

Segment Reporting [Abstract]

Segment Information

19. Segment information

The Company defines its operating segments as components of its business where separate financial information is available and used by the chief operating decision maker (“CODM”) in deciding how to allocate resources to its segments and in assessing performance. The Company’s CODM is its Chief Executive Officer.

The Company has identified two reportable segments for financial reporting purposes: Software and Client Engineering Services. The primary measure of segment operating performance is Adjusted EBITDA, which is defined as net income (loss) adjusted for income tax expense (benefit), interest expense, interest income and other, depreciation and amortization, stock-based compensation expense, restructuring charges, asset impairment charges and other special items as determined by management. Adjusted EBITDA includes an allocation of corporate headquarters costs.

The Software reportable segment derives revenue from the sale and lease of licenses for software products focused on the development and application of simulation technology to synthesize and optimize designs, processes and decisions for improved business performance. The Software segment also derives revenue from software support, upgrades, training and consulting services focused on product design and development expertise and analysis support from the component level up to complete product engineering at any stage of the lifecycle. To a much lesser extent, the Software segment also includes revenue from the sale of hardware products, primarily as a result of recent business acquisitions.

The Client Engineering Services reportable segment provides support to its customers with long-term ongoing product design and development expertise in its market segments of Solvers & Optimization, Modeling & Visualization, Industrial and Concept Design, and high performance computing. The Company hires simulation specialists, industrial designers, design engineers, materials experts, development and test specialists, manufacturing engineers and information technology specialists for placement at customer sites for specific customer-directed assignments.

The “All other” represents innovative services and products, including toggled ^®, the Company’s LED lighting business. toggled^® is focused on developing and selling next-generation solid state lighting technology along with communication and control protocols based on intellectual property for the direct replacement of fluorescent light tubes with LED lamps. Other businesses combined within Other include the Company’s WEYV business, which was terminated in the third quarter of 2019, and potential services and product concepts that are still in their development stages. See Note 4 – Acquisitions and disposals for further information about the termination of the WEYV business.

Inter-segment sales are not significant for any period presented. The CODM does not review asset information by segment when assessing performance, therefore no asset information is provided for reportable segments. The accounting policies of the segments are the same as those described in Note 2—Summary of significant accounting policies.

The following tables are in thousands:

Year ended December 31, 2019	Software		CES		All other			Total
Revenue	$	401,278	$	48,987	$	8,650		$	458,915
Adjusted EBITDA	$	38,834	$	5,255	$	(4,540	)	$	39,549

Year ended December 31, 2018	Software		CES		All other			Total
Revenue	$	341,306	$	47,852	$	7,221		$	396,379
Adjusted EBITDA	$	48,643	$	5,155	$	(3,618	)	$	50,180

Year ended December 31, 2017	Software		CES		All other			Total
Revenue	$	280,214	$	46,510	$	6,609		$	333,333
Adjusted EBITDA	$	22,864	$	4,966	$	(5,313	)	$	22,517

	Year ended December 31,
	2019			2018			2017
Reconciliation of Adjusted EBITDA to GAAP income (loss) before income taxes:
Adjusted EBITDA	$	39,549		$	50,180		$	22,517
Stock-based compensation expense		(8,528	)		(3,339	)		(47,281	)
Interest expense		(6,371	)		(200	)		(2,160	)
Interest income and other⁽¹⁾		260			(4,883	)		2,260
Depreciation and amortization		(21,522	)		(14,734	)		(11,747	)
Income (loss) before income taxes	$	3,388		$	27,024		$	(36,411	)

⁽¹⁾

	Revenue						Long-lived assets (1)
	Year ended December 31,						December 31,
	2019		2018		2017		2019		2018
United States	$	219,053	$	186,026	$	142,679	$	55,319	$	63,266
Other countries		14,753		8,604		6,404		10,190		11,447
Total Americas		233,806		194,630		149,083		65,509		74,713
Germany		50,102		45,664		43,751		3,405		4,305
France		17,210		16,154		18,128		1,224		1,583
Other countries		49,312		42,846		40,050		11,316		4,729
Total Europe, Middle East and Africa		116,624		104,664		101,929		15,945		10,617
Japan		37,757		35,478		33,686		2,036		2,045
Other countries		70,728		61,607		48,635		8,941		2,957
Total Asia Pacific		108,485		97,085		82,321		10,977		5,002
Total	$	458,915	$	396,379	$	333,333	$	92,431	$	90,332

(1)	Includes property and equipment, net and definite-lived intangible assets, net.

Retirement Benefits - Schedule of Pension Benefits Obligation (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Pension Plan [Abstract]
Accrued compensation and benefits	$ 596	$ 513
Other long-term liabilities	10,379	9,111
Components of pension benefits	$ 10,975	$ 9,624

Revenue from Contracts with Customers - Effect of Adoption of ASC 606 on Consolidated Statement of Operations (Detail) - USD ($)
$ / shares in Units, $ in Thousands

3 Months Ended

12 Months Ended

Dec. 31, 2019

Sep. 30, 2019

Jun. 30, 2019

Mar. 31, 2019

Dec. 31, 2018

Sep. 30, 2018

Jun. 30, 2018

Mar. 31, 2018

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

^[1]

Dec. 31, 2016

Revenue

$ 123,877

$ 100,406

$ 106,773

$ 127,859

$ 103,011

$ 86,751

$ 93,360

$ 113,257

$ 458,915

$ 396,379

$ 333,333

86,927

68,665

75,750

94,974

72,740

59,547

63,904

84,215

326,316

280,406

226,742

106,051

80,277

79,958

318,109

255,762

259,999

Income before income taxes

4,149

(10,507)

(3,202)

17,767

(3,557)

1,880

175

26,146

8,207

24,644

(33,257)

3,388

27,024

(36,411)

10,930

11,489

65,530

$ (1,502)

$ (15,939)

$ (3,120)

$ 13,019

$ (9,003)

$ 934

$ (1,080)

$ 24,684

$ (7,542)

$ 15,535

$ (101,941)

Income per share:

Basic

$ (0.02)

$ (0.22)

$ (0.04)

$ 0.18

$ (0.13)

$ 0.01

$ (0.02)

$ 0.39

$ (0.11)

$ 0.23

$ (1.94)

Diluted

$ (0.02)

$ (0.22)

$ (0.04)

$ 0.17

$ (0.13)

$ 0.01

$ (0.02)

$ 0.34

$ (0.11)

$ 0.21

$ (1.94)

License [Member]

Revenue

Prior to Adoption of ASC 606 [Member] | ASC 606 [Member]

$ 244,321

$ 207,164

Revenue

269,089

80,613

256,098

Income before income taxes

12,991

15,371

10,829

Prior to Adoption of ASC 606 [Member] | License [Member] | ASC 606 [Member]

$ 4,542

Income per share:

Basic

$ 0.07

Diluted

$ 0.06

Revenue

Adjustments for ASC 606 [Member] | ASC 606 [Member]

$ 195,847

Revenue

11,317

(336)

(336)

Income before income taxes

11,653

11,653

660

$ 200

Adjustments for ASC 606 [Member] | License [Member] | ASC 606 [Member]

$ 10,993

$ (200)

Income per share:

Basic

$ 0.16

Diluted

$ 0.15

Revenue

Accumulated Other Comprehensive Loss

$ 11,317

[1]	The year ended December 31, 2017 has been reported under ASC 605 and has not been adjusted under the modified retrospective approach of ASC 606. See Note 3 – Revenue from contracts with customers for the effect of the adoption of ASC 606 on the Company’s consolidated financial statements.

Accumulated Other Comprehensive Loss

12 Months Ended

Dec. 31, 2019

Equity [Abstract]

17. Accumulated other comprehensive loss

The components of accumulated other comprehensive loss are as follows (in thousands):

	Foreign currency translation			Retirement related benefit plans			Total
Balance at December 31, 2016	$	(5,725	)	$	(1,539	)	$	(7,264	)
Other comprehensive income (loss) before reclassification		2,351			(213	)		2,138
Amounts reclassified from accumulated other comprehensive loss		—			54			54
Tax effects		—			—			—
Other comprehensive income (loss)		2,351			(159	)		2,192
Balance at December 31, 2017		(3,374	)		(1,698	)		(5,072	)
Other comprehensive income (loss) before reclassification		(5,449	)		90			(5,359	)
Amounts reclassified from accumulated other comprehensive loss		—			(1,177	)		(1,177	)
Tax effects		—			318			318
Other comprehensive income (loss)		(5,449	)		(769	)		(6,218	)
Balance at December 31, 2018		(8,823	)		(2,467	)		(11,290	)
Other comprehensive income (loss) before reclassification		1,895			62			1,957
Amounts reclassified from accumulated other comprehensive loss		—			(179	)		(179	)
Tax effects		—			(16	)		(16	)
Other comprehensive income (loss)		1,895			(133	)		1,762
Balance at December 31, 2019	$	(6,928	)	$	(2,600	)	$	(9,528	)

Income Taxes - Reconciliation of Income Taxes Calculated at U.S. Federal Statutory Income Tax Rate (Detail) - USD ($)
$ in Thousands

12 Months Ended

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

U.S. federal statutory rate

21.00%

35.00%

Income taxes at U.S. federal statutory rate

$ 711

$ 5,675

$ (12,744)

Foreign income taxes at rates other than the federal statutory rate

1,247

2,179

373

U.S. state and local income taxes, net of U.S. federal tax benefit

(6,836)

(3,453)

(155)

U.S. Tax Cut and Jobs Act: transition tax, net of foreign tax credits

4,187

U.S. effect of foreign operations

8,609

Change in valuation allowance

18,138

21,544

49,859

Foreign withholding taxes

5,975

5,103

4,181

U.S. foreign tax credit

(7,059)

(5,648)

(4,154)

Research and development tax credit

(2,600)

(2,819)

(2,999)

(4,574)

(14,964)

10,871

Meals & entertainment

246

181

358

Other

(1,068)

1,206

(59)

Uncertain tax positions

(1,859)

903

446

Acquisition costs

503

Tax law changes

1,079

15,366

Summary of Fair value of Company's Stock Options Granted

$ 10,930

$ 11,489

$ 65,530

^[1]

[1]	The year ended December 31, 2017 has been reported under ASC 605 and has not been adjusted under the modified retrospective approach of ASC 606. See Note 3 – Revenue from contracts with customers for the effect of the adoption of ASC 606 on the Company’s consolidated financial statements.

Consolidated statements of comprehensive (loss) income (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Foreign currency translation, tax effect	$ 0	$ 0	$ 0
Retirement related benefit plans, tax effect	$ (16)	$ 318	$ 0

Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2019

The fair values of the Company’s stock options granted during the year ended December 31, 2019 and 2017, were estimated using the following assumptions:

	2019 grants			2017 grants
Weighted average grant date fair value per share	$	38.11		$1.86 - $1.94
Expected volatility		42	%		34	%
Expected term (in years)		6.25		5.75-6.25
Risk-free interest rate		1.80	%		2.02	%
Expected dividend yield		0	%		0	%

Summary of Stock-Based Compensation

Stock-based compensation expense

The stock-based compensation expense was recorded as follows (in thousands):

	Year ended December 31,
	2019		2018		2017
Cost of revenue-software	$	1,069	$	31	$	350
Research and development		2,917		740		12,540
Sales and marketing		2,250		910		7,693
General and administrative		2,292		1,658		26,698
Total stock-based compensation expense	$	8,528	$	3,339	$	47,281

NSO Plan [Member]

The following table summarizes the stock option activity under the NSO Plan:

	Number of options			Weighted average exercise price per share		Weighted average remaining contractual term (years)		Aggregate intrinsic value (in millions)
Outstanding at January 1, 2019		4,337,856		$	0.000025		18.0	$	119.6
Exercised		(780,420	)	$	0.000025
Forfeited		—		$	—
Outstanding and exercisable at December 31, 2019		3,557,436		$	0.000025		17.0	$	127.8

ISO Plan [Member]

The following table summarizes the stock option activity under the 2001 Stock-based compensation plans for the periods indicated as follows:

	Number of options			Weighted average exercise price per share		Weighted average remaining contractual term (years)		Aggregate intrinsic value (in millions)
Outstanding at January 1, 2019		532,220		$	0.65		1.4	$	14.3
Exercised		(429,220	)	$	0.66
Forfeited		—		$	—
Outstanding and exercisable at December 31, 2019		103,000		$	0.64		1.0	$	3.6

2012 Plan [Member]

The following table summarizes the stock option activity under the 2012 Plan for the periods indicated as follows:

	Number of options			Weighted average exercise price per share		Weighted average remaining contractual term (years)		Aggregate intrinsic value (in millions)
Outstanding at January 1, 2019		1,541,165		$	4.12		6.9	$	36.2
Granted		—		$	—
Exercised		(348,376	)	$	3.73
Forfeited		(8,972	)	$	4.64
Outstanding at December 31, 2019		1,183,817		$	4.23		6.1
Exercisable at December 31, 2019		893,349		$	3.96		5.7	$	37.5

2017 Plan [Member]

Summary of Restricted Stock Units Awarded

The following table summarizes the stock option activity under the 2017 Plan for the period:

	Number of options		Weighted average exercise price per share		Weighted average remaining contractual term (years)		Aggregate intrinsic value (in millions)
Outstanding at January 1, 2019		—	$	—		—		—
Granted		20,000	$	38.11
Exercised		—	$	—
Forfeited		—	$	—
Outstanding at December 31, 2019		20,000	$	38.11		9.2
Exercisable at December 31, 2019		—

The following table summarizes the restricted stock units, or RSUs, awarded under the 2017 Plan for the period:

	Number of RSUs
Outstanding at January 1, 2019		206,061
Granted		694,690
Vested		(60,388	)
Forfeited		(59,062	)
Outstanding at December 31, 2019		781,301

Segment Information - Additional Information (Detail)	12 Months Ended
Segment Information - Additional Information (Detail)	Dec. 31, 2019 Segment
Segment Reporting [Abstract]
Number of reportable segments	2

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2019

Effect of Error Correction on Company's Financial Statements

The following table presents the effect of the error corrections on the Company’s consolidated balance sheet for the period indicated (in thousands):

	As of December 31, 2018
	As Reported			Adjustments			As Corrected
Deferred tax assets	$	1,373		$	3,981		$	5,354
Total assets	$	483,216		$	3,981		$	487,197
Other accrued expenses and current liabilities	$	27,565		$	(526	)	$	27,039
Total current liabilities	$	127,758		$	(526	)	$	127,232
Other long-term liabilities	$	28,153		$	(2,397	)	$	25,756
Total liabilities	$	194,082		$	(2,923	)	$	191,159
Accumulated deficit	$	(82,005	)	$	7,142		$	(74,863	)
Accumulated other comprehensive loss	$	(11,052	)	$	(238	)	$	(11,290	)
Total stockholders' equity	$	286,782		$	6,904		$	293,686
Total liabilities, mezzanine equity and stockholders' equity	$	483,216		$	3,981		$	487,197

The following tables present the effect of the error corrections on the consolidated statements of operations for the periods indicated (in thousands, except per share data):

	Year Ended December 31, 2018
	As Reported		Adjustments			As Corrected
Income before income taxes	$	27,024	$	—		$	27,024
Income tax expense	$	13,309	$	(1,820	)	$	11,489
Net income	$	13,715	$	1,820		$	15,535
Net income per share attributable to common stockholders, basic	$	0.20	$	0.03		$	0.23
Net income per share attributable to common stockholders, diluted	$	0.18	$	0.03		$	0.21

	Year Ended December 31, 2017
	As Reported			Adjustments			As Corrected
Loss before income taxes	$	(36,411	)	$	—		$	(36,411	)
Income tax expense	$	62,996		$	2,534		$	65,530
Net loss	$	(99,407	)	$	(2,534	)	$	(101,941	)
Net loss per share attributable to common stockholders, basic	$	(1.89	)	$	(0.05	)	$	(1.94	)
Net loss per share attributable to common stockholders, diluted	$	(1.89	)	$	(0.05	)	$	(1.94	)

Reconciliation of Cash, Cash Equivalents and Restricted Cash

The following table provides a reconciliation of cash, cash equivalents and restricted cash reported in the consolidated balance sheets that sum to the total of the amounts reported in the consolidated statements of cash flows (in thousands):

	December 31,
	2019		2018
Cash and cash equivalents	$	223,117	$	35,345
Restricted cash included in other long-term assets		380		340
Total cash, cash equivalents, and restricted cash	$	223,497	$	35,685

Schedule of Accounts Receivable Net

Accounts receivable, net consisted of the following (in thousands):

	December 31,
	2019		2018
Accounts receivable, trade	$	100,461	$	93,073
Contract assets		4,523		3,730
Accounts receivable, net	$	104,984	$	96,803

Schedule of Allowance for Doubtful Accounts

Activity in the allowance for doubtful accounts was as follows (in thousands):

	For the year ended December 31,
	2019			2018			2017
Balance, beginning of year	$	(1,150	)	$	(798	)	$	(565	)
Provision charged to expense		(671	)		(394	)		(610	)
Write-offs, net of recoveries		413			3			414
Effects of foreign currency translation		(7	)		39			(37	)
Balance, end of year	$	(1,415	)	$	(1,150	)	$	(798	)

Schedule of Other Income, Net

Other income, net consists of the following (in thousands):

	Year ended December 31,
	2019			2018			2017
Foreign exchange loss (gain)	$	745		$	(626	)	$	1,254
Other		(2,297	)		(1,954	)		(260	)
Other (income) expense, net	$	(1,552	)	$	(2,580	)	$	994

Retirement Benefits - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Compensation And Retirement Disclosure [Abstract]
Funded percentage	80.00%
Defined Benefit Plan, Contributions by Employer	$ 1,600	$ 1,300	$ 1,100
Net benefit cost	1,800	1,200	1,200
Benefit obligation benefits paid	400	400	$ 200
Accumulated benefit obligation	6,800	6,000
Defined benefit plan assets	900
Defined benefit plan, benefit obligation	$ 10,975	$ 9,624

Stockholders' Equity - Additional Information (Detail)	12 Months Ended
Stockholders' Equity - Additional Information (Detail)	Dec. 31, 2019 Vote $ / shares shares	Dec. 31, 2018 $ / shares shares	Dec. 31, 2017 $ / shares	Oct. 05, 2017 $ / shares
Class of Stock [Line Items]
Preferred stock, shares authorized \| shares	45,000,000	45,000,000
Preferred stock, par value \| $ / shares	$ 0.0001	$ 0.0001
Preferred stock, shares issued \| shares	0	0
Preferred stock, shares outstanding \| shares	0	0
Common stock, par value \| $ / shares				$ 0.0001
Common stock dividends \| $ / shares	$ 0	$ 0	$ 0
Class A Common Stock [Member]
Class of Stock [Line Items]
Common stock, shares authorized \| shares	513,796,572	513,797,000
Common stock, par value \| $ / shares	$ 0.0001	$ 0.0001
Number of votes entitled per share \| Vote	1
Class B Common Stock [Member]
Class of Stock [Line Items]
Common stock, shares authorized \| shares	41,203,428	41,203,000
Common stock, par value \| $ / shares	$ 0.0001	$ 0.0001
Number of votes entitled per share \| Vote	10

(Loss) Income Per Share (Tables)

12 Months Ended

Dec. 31, 2019

Earnings Per Share [Abstract]

Computation of Numerators and Denominators Used in Basic and Diluted (Loss) Income Per Share Amounts

The following table sets forth the computation of the numerators and denominators used in the basic and diluted (loss) income per share amounts (in thousands, except per share data):

	Year ended December 31,
	2019			2018		2017
Numerator:
Net (loss) income	$	(7,542	)	$	15,535	$	(101,941	)
Denominator:
Denominator for basic (loss) income per share— weighted average shares		71,544			67,468		52,466
Effect of dilutive securities, stock options and RSUs		—			7,410		—
Denominator for dilutive (loss) income per share		71,544			74,878		52,466
Net (loss) income per share attributable to common stockholders, basic	$	(0.11	)	$	0.23	$	(1.94	)
Net (loss) income per share attributable to common stockholders, diluted	$	(0.11	)	$	0.21	$	(1.94	)

Leases - Schedule of Supplemental Cash Flow Information Related to Leases (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($)
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$ (11,355)
Operating cash flows from finance leases	(46)
Financing cash flows from finance leases	(438)
ROU assets obtained in exchange for lease obligations:
Operating leases	11,251
Finance leases	$ 632

Income Taxes - Significant Components of Income Tax Expense (Detail) - USD ($)
$ in Thousands

12 Months Ended

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

Current

U.S. Federal

$ 0

$ 2

$ 0

Non-U.S.

11,434

12,629

10,290

U.S. State and Local

446

(16)

135

Total current

11,880

12,615

10,425

Deferred

U.S. Federal

193

1,714

54,130

Non-U.S.

(1,143)

(2,823)

1,228

U.S. State and Local

(17)

(253)

Total deferred

(950)

(1,126)

55,105

$ 10,930

$ 11,489

$ 65,530

^[1]

[1]	The year ended December 31, 2017 has been reported under ASC 605 and has not been adjusted under the modified retrospective approach of ASC 606. See Note 3 – Revenue from contracts with customers for the effect of the adoption of ASC 606 on the Company’s consolidated financial statements.

Property and Equipment, Net - Summary of Property and Equipment (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 82,603	$ 70,580
Less: accumulated depreciation and amortization	46,306	40,427
Property and equipment, net	36,297	30,153
Land [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 9,942	7,994
Property, Plant and Equipment, Estimated Useful Lives	Indefinite
Building and Improvements [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 15,512	13,120
Building and Improvements [Member] \| Minimum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life	5 years
Building and Improvements [Member] \| Maximum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life	39 years
Computer Equipment and Software [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 37,361	34,582
Computer Equipment and Software [Member] \| Minimum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life	3 years
Computer Equipment and Software [Member] \| Maximum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life	5 years
Office Furniture and Equipment [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 8,029	7,958
Office Furniture and Equipment [Member] \| Minimum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life	5 years
Office Furniture and Equipment [Member] \| Maximum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life	15 years
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 9,014	$ 6,926
Leasehold Improvements [Member] \| Minimum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life	5 years
Leasehold Improvements [Member] \| Maximum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life	10 years
Right-of-Use Assets Under Finance Leases [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 2,745
Right-of-Use Assets Under Finance Leases [Member] \| Minimum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life	5 years
Right-of-Use Assets Under Finance Leases [Member] \| Maximum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life	10 years

Income Taxes - Additional Information (Detail) - USD ($)
$ in Thousands

12 Months Ended

Dec. 31, 2020

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

U.S. Federal statutory income tax rate

21.00%

35.00%

Tax cuts and job act, transition tax liability, net of foreign tax credits

$ 4,187

Tax cuts and job act, additional transition tax liability, net of foreign tax credits

$ 600

Tax benefit in other

200

Tax benefit

$ (10,930)

(11,489)

$ (65,530)

^[1]

Offset by deferred tax expense recorded for business combinations

12,600

Gross unrecognized tax benefits recognized would affect the effective tax rate

8,200

Scenario Forecast [Member]

Reduction in unrecognized tax benefits which if recognized would impact effective tax rate in next 12 months

$ 400

ASC 606 [Member]

Other Comprehensive Income [Member]

Tax benefit in other

12,600

Issuance of Convertible Debt [Member]

Tax benefit

$ 200

Goodwill And Intangible Assets Disclosure [Abstract]

Tax benefit in other

$ 11,900

[1]	The year ended December 31, 2017 has been reported under ASC 605 and has not been adjusted under the modified retrospective approach of ASC 606. See Note 3 – Revenue from contracts with customers for the effect of the adoption of ASC 606 on the Company’s consolidated financial statements.

Goodwill and Other Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2019

Changes in Carrying Amount of Goodwill Attributable to Software Reportable Segment

The changes in the carrying amount of goodwill, which is attributable to the Software reportable segment, are as follows (in thousands):

Balance at December 31, 2017	$	62,706
Acquisitions		152,630
Effects of foreign currency translation and other		(4,804	)
Balance at December 31, 2018		210,532
Acquisitions		21,922
Effects of foreign currency translation and other		1,229
Balance at December 31, 2019	$	233,683

Schedule of Other Intangible Assets

A summary of other intangible assets is shown below (in thousands):

	December 31, 2019
	Weighted average amortization period	Gross carrying amount		Accumulated amortization		Net carrying amount
Definite-lived intangible assets:
Developed technology	4-6 years	$	60,916	$	25,838	$	35,078
Customer relationships	7-10 years		32,582		11,575		21,007
Other intangibles	10 years		111		62		49
Total definite-lived intangible assets			93,609		37,475		56,134
Indefinite-lived intangible assets:
Trade names			10,941				10,941
Total other intangible assets		$	104,550	$	37,475	$	67,075

	December 31, 2018
	Weighted average amortization period	Gross carrying amount		Accumulated amortization		Net carrying amount
Definite-lived intangible assets:
Developed technology	4-6 years	$	54,530	$	15,517	$	39,013
Customer relationships	7-10 years		28,422		7,309		21,113
Other intangibles	10 years		109		56		53
Total definite-lived intangible assets			83,061		22,882		60,179
Indefinite-lived intangible assets:
Trade names			9,657				9,657
Total other intangible assets		$	92,718	$	22,882	$	69,836

Summary of Estimated Amortization Expense

Estimated amortization expense for the next five years as of December 31, 2019 is as follows (in thousands):

Year ending
December 31, 2020	$	15,004
December 31, 2021	$	12,664
December 31, 2022	$	9,466
December 31, 2023	$	8,276
December 31, 2024	$	6,490
Thereafter	$	4,234
Total	$	56,134

Summary of Significant Accounting Policies - Additional Information (Detail)

3 Months Ended

12 Months Ended

Oct. 05, 2017

$ / shares

Dec. 31, 2019

USD ($)

$ / shares

Sep. 30, 2019

USD ($)

Jun. 30, 2019

USD ($)

Mar. 31, 2019

USD ($)

Dec. 31, 2018

USD ($)

$ / shares

Sep. 30, 2018

USD ($)

Jun. 30, 2018

USD ($)

Mar. 31, 2018

USD ($)

Dec. 31, 2019

USD ($)

Customer

$ / shares

Dec. 31, 2018

USD ($)

Customer

$ / shares

Dec. 31, 2017

USD ($)

Customer

$ / shares

Dec. 31, 2016

USD ($)

$ / shares

Jan. 01, 2019

USD ($)

Stockholders' equity

$ 354,707,000

$ 293,686,000

$ 354,707,000

$ 293,686,000

10,930,000

11,489,000

$ 65,530,000

^[1]

Common stock, par value | $ / shares

$ (1,502,000)

$ (15,939,000)

$ (3,120,000)

$ 13,019,000

$ (9,003,000)

$ 934,000

$ (1,080,000)

$ 24,684,000

$ (7,542,000)

$ 15,535,000

(101,941,000)

^[1]

Stock split ratio

$ 0.0001

Common stock conversion description

Preferred stock, shares authorized | shares

45,000,000

Allowance for doubtful accounts

$ 1,415,000

$ 1,150,000

$ 1,415,000

$ 1,150,000

$ 798,000

$ 565,000

Number of individual customer accounted for 10% or more of revenue | Customer

Inventory

2,400,000

2,000,000.0

$ 2,400,000

$ 2,000,000.0

Impairment losses

$ 0

Impairment of intangible assets

608,000

Income tax receivable, current

7,264,000

4,431,000

7,264,000

4,431,000

Research and development expenses

117,510,000

97,592,000

93,234,000

^[1]

Advertising expenses

4,500,000

$ 4,400,000

$ 3,500,000

Operating lease liabilities

29,315,000

Operating lease ROU assets

28,134,000

$ 28,134,000

Restricted Stock Units (RSUs) [Member]

Stock-based compensation awards requisite service period

4 years

Ministry of the Economy, Finance and Industry, France [Member] | Research and Development Tax Credit Carryforward [Member]

Tax credit carryforward, period

3 years

Income tax receivable

12,100,000

11,700,000

$ 12,100,000

$ 11,700,000

Income tax receivable, current

2,500,000

2,600,000

2,500,000

2,600,000

Income tax receivable, noncurrent

$ 9,600,000

$ 9,100,000

$ 9,600,000

$ 9,100,000

Product Concentration Risk [Member] | Sales Revenue, Net [Member] | Automotive Industry [Member]

Concentration of credit risk, percentage

40.00%

45.00%

50.00%

Class B Common Stock [Member]

Common stock, par value | $ / shares

$ 0.0001

Common stock conversion | shares

2,495,752

Common stock, shares authorized | shares

41,203,428

41,203,000

41,203,428

41,203,000

Class B Common Stock [Member] | Maximum [Member]

Percentage of stock held by holders

3.00%

Class A Common Stock [Member]

Common stock, par value | $ / shares

$ 0.0001

Common stock, shares authorized | shares

513,796,572

513,797,000

513,796,572

513,797,000

Class A Common Stock [Member] | Put Option [Member]

Put right exercise period from date of purchase

5 years

Shares issued | shares

200,000

Put right, exercise price | $ / shares

$ 12.50

ASU 2016-02 [Member]

Operating lease liabilities

$ 30,100,000

Operating lease ROU assets

$ 29,100,000

Adjustments [Member] | ASC 606 [Member]

Stockholders' equity

$ 1,600,000

900,000

$ 660,000

200,000

Net income per share attributable to common stockholders (basic and diluted) | $ / shares

$ 10,993,000

$ (200,000)

$ (0.01)

[1]	The year ended December 31, 2017 has been reported under ASC 605 and has not been adjusted under the modified retrospective approach of ASC 606. See Note 3 – Revenue from contracts with customers for the effect of the adoption of ASC 606 on the Company’s consolidated financial statements.

Acquisitions and Disposals - Summary of Amounts of Identified Assets Acquired and Liabilities Assumed at the Acquisition Date (Detail) - USD ($) $ in Thousands	Dec. 13, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Recognized amounts of identifiable assets acquired and liabilities assumed:
Goodwill		$ 233,683	$ 210,532	$ 62,706
Datawatch Corporation [Member]
Business Acquisition [Line Items]
Fair value of consideration transferred	$ 183,427
Recognized amounts of identifiable assets acquired and liabilities assumed:
Cash	8,278
Accounts receivable	10,384
Other assets	2,522
Property and equipment	980
Accounts payable and other liabilities	(5,041)
Deferred revenue	(3,649)
Other long-term liabilities	(8,340)
Total net identifiable assets acquired and liabilities assumed	51,834
Goodwill	131,593
Datawatch Corporation [Member] \| Trade Names [Member]
Recognized amounts of identifiable assets acquired and liabilities assumed:
Indefinite-lived intangibles	7,400
Datawatch Corporation [Member] \| Developed Technology [Member]
Recognized amounts of identifiable assets acquired and liabilities assumed:
Finite-lived intangibles	22,600
Datawatch Corporation [Member] \| Customer Relationships [Member]
Recognized amounts of identifiable assets acquired and liabilities assumed:
Finite-lived intangibles	$ 16,700

Segment Information - Schedule of Segment Reporting Information (Detail) - USD ($)
$ in Thousands

3 Months Ended

12 Months Ended

Dec. 31, 2019

Sep. 30, 2019

Jun. 30, 2019

Mar. 31, 2019

Dec. 31, 2018

Sep. 30, 2018

Jun. 30, 2018

Mar. 31, 2018

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

$ 123,877

$ 100,406

$ 106,773

$ 127,859

$ 103,011

$ 86,751

$ 93,360

$ 113,257

$ 458,915

$ 396,379

$ 333,333

^[1]

39,549

50,180

22,517

Software [Member]

401,278

341,306

280,214

38,834

48,643

22,864

CES [Member]

48,987

47,852

46,510

5,255

5,155

4,966

All Other [Member]

8,650

7,221

6,609

Valuation And Qualifying Accounts [Abstract]

$ (4,540)

$ (3,618)

$ (5,313)

[1]	The year ended December 31, 2017 has been reported under ASC 605 and has not been adjusted under the modified retrospective approach of ASC 606. See Note 3 – Revenue from contracts with customers for the effect of the adoption of ASC 606 on the Company’s consolidated financial statements.

Schedule II - Valuation and Qualifying Accounts

12 Months Ended

Dec. 31, 2019

Schedule II - Valuation and Qualifying Accounts

Schedule II – Valuation and Qualifying Accounts

(in thousands)

	Balance at beginning of year		Additions		Deductions			Balance at end of year
Allowance for Doubtful Accounts
Year ended December 31, 2019	$	1,150	$	671	$	(406	)	$	1,415
Year ended December 31, 2018	$	798	$	394	$	(42	)	$	1,150
Year ended December 31, 2017	$	565	$	610	$	(377	)	$	798

Debt (Tables)

12 Months Ended

Dec. 31, 2019

Debt Disclosure [Abstract]

Schedule of Carrying Value of Debt

The carrying value of debt is as follows (in thousands):

	December 31,
	2019		2018
Convertible senior notes	$	230,000	$	—
Revolving credit facility		—		30,950
Obligations for finance leases		1,174		813
Other borrowings		—		75
Total debt		231,174		31,838
Less: unamortized debt discount		46,820		—
Less: unamortized debt issuance costs		5,686		90
Less: current portion of long-term debt		430		331
Long-term debt, net of current portion	$	178,238	$	31,417

Schedule of Net Carrying Value of Liability Component of Convertible Notes

The net carrying value of the liability component of the Convertible Notes was as follows (in thousands):

	December 31,
	2019
Principal	$	230,000
Less: unamortized debt discount		46,820
Less: unamortized debt issuance costs		5,686
Net carrying amount	$	177,494

Schedule of Net Carrying Value of Equity Component of Convertible Notes

The net carrying value of the equity component of the Convertible Notes was as follows (in thousands):

	December 31,
	2019
Proceeds allocated to the conversion option (debt discount)	$	51,842
Less: issuance costs		1,833
Net carrying amount	$	50,009

Schedule of Interest Expense Related to Convertible Notes

The interest expense related to the Convertible Notes was as follows (in thousands):

	For the Year Ended December 31,
	2019
Contractual interest expense	$	313
Amortization of debt issuance cost and discount		5,635
Total	$	5,948

Goodwill and Other Intangible Assets - Schedule of Other Intangible Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Summary Of Other Intangible Assets [Line Items]
Gross carrying amount	$ 93,609	$ 83,061
Accumulated amortization	37,475	22,882
Net carrying amount	56,134	60,179
Gross carrying amount	104,550	92,718
Accumulated amortization	37,475	22,882
Net carrying amount	67,075	69,836
Developed Technology [Member]
Summary Of Other Intangible Assets [Line Items]
Gross carrying amount	60,916	54,530
Accumulated amortization	25,838	15,517
Net carrying amount	$ 35,078	$ 39,013
Developed Technology [Member] \| Minimum [Member]
Summary Of Other Intangible Assets [Line Items]
Weighted-average useful life of acquired finite-lived intangible assets	4 years	4 years
Developed Technology [Member] \| Maximum [Member]
Summary Of Other Intangible Assets [Line Items]
Weighted-average useful life of acquired finite-lived intangible assets	6 years	6 years
Customer Relationships [Member]
Summary Of Other Intangible Assets [Line Items]
Gross carrying amount	$ 32,582	$ 28,422
Accumulated amortization	11,575	7,309
Net carrying amount	$ 21,007	$ 21,113
Customer Relationships [Member] \| Minimum [Member]
Summary Of Other Intangible Assets [Line Items]
Weighted-average useful life of acquired finite-lived intangible assets	7 years	7 years
Customer Relationships [Member] \| Maximum [Member]
Summary Of Other Intangible Assets [Line Items]
Weighted-average useful life of acquired finite-lived intangible assets	10 years	10 years
Other Intangibles [Member]
Summary Of Other Intangible Assets [Line Items]
Weighted-average useful life of acquired finite-lived intangible assets	10 years	10 years
Gross carrying amount	$ 111	$ 109
Accumulated amortization	62	56
Net carrying amount	49	53
Trade Names [Member]
Summary Of Other Intangible Assets [Line Items]
Net carrying amount	$ 10,941	$ 9,657

Disposals WEYV - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
WEYV [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups [Line Items]
Loss before income tax	$ (3.0)	$ (4.2)

Supplemental Quarterly Financial Information (Unaudited)

12 Months Ended

Dec. 31, 2019

Quarterly Financial Information Disclosure [Abstract]

Supplemental Quarterly Financial Information (Unaudited)

20. Supplemental quarterly financial information (unaudited)

related notes. These quarterly operating results are not necessarily indicative of the Company’s operating results for a full year or any future period.

	Three months ended
(in thousands, except per share data)	March 31, 2019		June 30, 2019			September 30, 2019			December 31, 2019
Total revenue	$	127,859	$	106,773		$	100,406		$	123,877
Gross profit	$	94,974	$	75,750		$	68,665		$	86,927
Operating income (loss)	$	17,767	$	(3,202	)	$	(10,507	)	$	4,149
Net income (loss)	$	13,019	$	(3,120	)	$	(15,939	)	$	(1,502	)
Net income (loss) per share, basic	$	0.18	$	(0.04	)	$	(0.22	)	$	(0.02	)
Net income (loss) per share, diluted	$	0.17	$	(0.04	)	$	(0.22	)	$	(0.02	)

	Three months ended
(in thousands, except per share data)	March 31, 2018		June 30, 2018			September 30, 2018		December 31, 2018
Total revenue	$	113,257	$	93,360		$	86,751	$	103,011
Gross profit	$	84,215	$	63,904		$	59,547	$	72,740
Operating income (loss)	$	26,146	$	175		$	1,880	$	(3,557	)
Net income (loss)	$	24,684	$	(1,080	)	$	934	$	(9,003	)
Net income (loss) per share, basic	$	0.39	$	(0.02	)	$	0.01	$	(0.13	)
Net income (loss) per share, diluted	$	0.34	$	(0.02	)	$	0.01	$	(0.13	)

Operating income in the first quarter of 2018 includes a non-recurring adjustment for a change in estimated legal expenses of $2.0 million of income.

Operating income in the third quarter of 2018 includes a gain on the sale of a building for $4.4 million.

The net loss in the fourth quarter of 2018 is primarily the result of transaction costs from the acquisition of Datawatch. See Note 4 – Acquisitions and disposals.

Segment Information - Reconciliation of U.S. GAAP Income (Loss) Before Income Taxes to Adjusted EBITDA (Detail) - USD ($)
$ in Thousands

12 Months Ended

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

Segment Reporting [Abstract]

Stock-based compensation expense

$ 39,549

$ 50,180

$ 22,517

(8,528)

(3,339)

(47,281)

Interest expense

(6,371)

(200)

(2,160)

^[1]

Interest income and other

260

(4,883)

2,260

Depreciation and amortization

(21,522)

(14,734)

(11,747)

$ 3,388

$ 27,024

$ (36,411)

^[1]

[1]	The year ended December 31, 2017 has been reported under ASC 605 and has not been adjusted under the modified retrospective approach of ASC 606. See Note 3 – Revenue from contracts with customers for the effect of the adoption of ASC 606 on the Company’s consolidated financial statements.

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2019