Altair Engineering (ALTR) 10-K 1 Mar 19 2018 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2018	Feb. 15, 2019	Jun. 29, 2018
Document Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	FY
Trading Symbol	ALTR
Entity Registrant Name	ALTAIR ENGINEERING INC.
Entity Central Index Key	1,701,732
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 1.2
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Class A Common Stock [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		38,507,315
Class B Common Stock [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		32,170,732

Consolidated balance sheets

Consolidated balance sheets - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
CURRENT ASSETS
Cash and cash equivalents	$ 35,345	$ 39,213
Accounts receivable, net	96,803	86,635
Inventory, net	1,964	1,980
Income tax receivable	4,431	6,054
Prepaid expenses and other current assets	15,491	10,006
Total current assets	154,034	143,888
Property and equipment, net	30,153	31,446
Goodwill	210,532	62,706
Other intangible assets, net	69,836	24,461
Deferred tax assets	1,373	8,351
Other long-term assets	17,288	17,019
TOTAL ASSETS	483,216	287,871
CURRENT LIABILITIES
Current portion of long-term debt	331	232
Accounts payable	8,357	4,880
Accrued compensation and benefits	31,740	26,560
Obligations for acquisition of businesses	1,218	13,925
Other accrued expenses and current liabilities	26,347	21,744
Deferred revenue	59,765	130,122
Total current liabilities	127,758	197,463
Long-term debt, net of current portion	31,417	178
Deferred revenue, non-current	6,754	9,640
Other long-term liabilities	28,153	17,647
TOTAL LIABILITIES	194,082	224,928
Commitments and contingencies
MEZZANINE EQUITY	2,352	2,352
STOCKHOLDERS’ EQUITY
Preferred stock ($0.0001 par value), authorized 45,000 shares, none issued and outstanding
Additional paid-in capital	379,832	232,156
Accumulated deficit	(82,005)	(166,499)
Accumulated other comprehensive loss	(11,052)	(5,072)
TOTAL STOCKHOLDERS’ EQUITY	286,782	60,591
TOTAL LIABILITIES, MEZZANINE EQUITY AND STOCKHOLDERS’ EQUITY	483,216	287,871
Class A Common Stock [Member]
STOCKHOLDERS’ EQUITY
Common stock	4	2
Class B Common Stock [Member]
STOCKHOLDERS’ EQUITY
Common stock	$ 3	$ 4

Consolidated balance sheets (Pa

Consolidated balance sheets (Parenthetical) - $ / shares	Dec. 31, 2018	Dec. 31, 2017
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	513,797,000	513,797,000
Common stock, shares issued	38,349,000	26,725,000
Common stock, shares outstanding	38,349,000	26,725,000
Class B Common Stock [Member]
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	41,203,000	41,203,000
Common stock, shares issued	32,171,000	36,508,000
Common stock, shares outstanding	32,171,000	36,508,000

Consolidated statements of oper

Consolidated statements of operations - USD ($) shares in Thousands, $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Total revenue	[1]	$ 396,379	$ 333,333	$ 313,240
Total cost of revenue	[1]	115,973	106,591	102,600
Gross profit	[1]	280,406	226,742	210,640
Operating expenses
Research and development	[1]	97,592	93,234	71,325
Sales and marketing	[1]	80,277	79,958	66,086
General and administrative	[1]	79,751	87,979	57,202
Amortization of intangible assets	[1]	7,739	5,448	3,322
Other operating income	[1]	(9,597)	(6,620)	(2,742)
Total operating expenses	[1]	255,762	259,999	195,193
Operating income (loss)	[1]	24,644	(33,257)	15,447
Interest expense	[1]	200	2,160	2,265
Other (income) expense, net	[1]	(2,580)	994	(520)
Income (loss) before income taxes	[1]	27,024	(36,411)	13,702
Income tax expense	[1]	13,309	62,996	3,539
Net income (loss)	[1]	$ 13,715	$ (99,407)	$ 10,163
Income (loss) per share:
Net income (loss) per share attributable to common stockholders, basic	[1]	$ 0.20	$ (1.89)	$ 0.21
Net income (loss) per share attributable to common stockholders, diluted	[1]	$ 0.18	$ (1.89)	$ 0.18
Weighted average shares outstanding:
Weighted average number of shares used in computing net income (loss) per share, basic	[1]	67,468	52,466	48,852
Weighted average number of shares used in computing net income (loss) per share, diluted	[1]	74,878	52,466	57,856
License [Member]
Total revenue	[1]	$ 207,164
Total cost of revenue	[1]	16,119
Maintenance and Other Services [Member]
Total revenue	[1]	97,197
Total cost of revenue	[1]	29,655
Total Software [Member]
Total revenue	[1]	304,361	$ 244,817	$ 223,818
Total cost of revenue	[1]	45,774	36,360	31,962
Software Related Services [Member]
Total revenue	[1]	36,945	35,397	35,770
Total cost of revenue	[1]	26,415	26,888	27,653
Total Software and Related Services [Member]
Total revenue	[1]	341,306	280,214	259,588
Total cost of revenue	[1]	72,189	63,248	59,615
Client Engineering Services [Member]
Total revenue	[1]	47,852	46,510	47,702
Total cost of revenue	[1]	38,979	38,131	38,106
Other [Member]
Total revenue	[1]	7,221	6,609	5,950
Total cost of revenue	[1]	$ 4,805	$ 5,212	$ 4,879
[1]	The year ended December 31, 2018 has been reported under ASC 606, and the years ended December 31, 2017 and 2016 have been reported under ASC 605 and have not been adjusted under the modified retrospective approach. 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 comp

Consolidated statements of comprehensive (loss) income - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Net income (loss)	[1]	$ 13,715	$ (99,407)	$ 10,163
Other comprehensive (loss) income, net of tax:
Foreign currency translation (net of tax effect of $0, $0 and ($60) respectively)		(5,211)	2,351	20
Retirement related benefit plans (net of tax effect of $318, $0 and $195, respectively)		(769)	(159)	(576)
Total other comprehensive (loss) income		(5,980)	2,192	(556)
Comprehensive income (loss)		$ 7,735	$ (97,215)	$ 9,607
[1]	The year ended December 31, 2018 has been reported under ASC 606, and the years ended December 31, 2017 and 2016 have been reported under ASC 605 and have not been adjusted under the modified retrospective approach. 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 co_2

Consolidated statements of comprehensive (loss) income (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Foreign currency translation, tax effect	$ 0	$ 0	$ (60)
Retirement related benefit plans, tax effect	$ 318	$ 0	$ 195

Consolidated statement of chang

Consolidated statement of changes in stockholders' equity (deficit) - USD ($) shares in Thousands, $ in Thousands	Total		IPO [Member]	Common StockClass A Common Stock [Member]	Common StockClass A Common Stock [Member]IPO [Member]	Common StockClass B Common Stock [Member]	Common StockClass B Common Stock [Member]IPO [Member]	Additional Paid-in Capital [Member]	Additional Paid-in Capital [Member]IPO [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Loss [Member]	Total Altair Engineering' Inc. Stockholders' Equity (Deficit) [Member]	Total Altair Engineering' Inc. Stockholders' Equity (Deficit) [Member]IPO [Member]	Non-controlling Interest [Member]
Beginning balance at Dec. 31, 2015	$ (42,039)			$ 1		$ 4		$ 41,909		$ (77,255)	$ (6,708)	$ (42,049)		$ 10
Beginning balance (in shares) at Dec. 31, 2015				5,748		41,680
Net income (loss)	10,163	[1]								10,163		10,163
Issuance of common stock	456							456				456
Issuance of common stock (in shares)				3,484
Stock redemptions	(3,291)							(3,291)				(3,291)
Stock redemptions, (in shares)				(332)		(476)
Stock-based compensation	614							614				614
Foreign currency translation, net of tax	20										20	20
Retirement related benefit plans, net of tax	(576)										(576)	(576)
Ending balance at Dec. 31, 2016	(34,653)			$ 1		$ 4		39,688		(67,092)	(7,264)	(34,663)		10
Ending balance (in shares) at Dec. 31, 2016				8,900		41,204
Net income (loss)	(99,407)	[1]								(99,407)		(99,407)
Issuance of common stock			$ 114,438		$ 1				$ 114,437				$ 114,438
Issuance of common stock (in shares)					13,800		(2,200)
Shares converted upon Delaware incorporation (in shares)				2,496		(2,496)
2001 ISO Plan modification	66,510							66,510				66,510
Issuance of common stock for acquisitions	8,712							8,712				8,712
Issuance of common stock for acquisitions (in shares)				988
Exercise of stock options	1,792							1,792				1,792
Exercise of stock options (in shares)				541
Purchase of noncontrolling interests	(29)							(19)				(19)		$ (10)
Amortization of mezzanine equity	(8)							(8)				(8)
Stock-based compensation	1,044							1,044				1,044
Foreign currency translation, net of tax	2,351										2,351	2,351
Retirement related benefit plans, net of tax	(159)										(159)	(159)
Ending balance at Dec. 31, 2017	60,591			$ 2		$ 4		232,156		(166,499)	(5,072)	60,591
Ending balance (in shares) at Dec. 31, 2017				26,725		36,508
Net income (loss)	13,715	[1]								13,715		13,715
Follow-on public offering, net of offering costs of $370	135,201			$ 1		$ (1)		135,201				135,201
Follow-on public offering, net of offering costs of $370 (shares)				5,731		(1,675)
Adjustment for acquisitions	(96)							(96)				(96)
Conversion from Class B to Class A				2,662		(2,662)
Issuance of common stock for acquisitions	8,681							8,681				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
Stock-based compensation	1,814							1,814				1,814
Foreign currency translation, net of tax	(5,211)										(5,211)	(5,211)
Retirement related benefit plans, net of tax	(769)										(769)	(769)
Ending balance at Dec. 31, 2018	286,782			$ 4		$ 3		$ 379,832		(82,005)	$ (11,052)	286,782
Ending balance (in shares) at Dec. 31, 2018				38,349		32,171
Cumulative effect of an accounting change	$ 70,779									$ 70,779		$ 70,779
[1]	The year ended December 31, 2018 has been reported under ASC 606, and the years ended December 31, 2017 and 2016 have been reported under ASC 605 and have not been adjusted under the modified retrospective approach. 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 statement of cha_2

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

Consolidated statements of cash

Consolidated statements of cash flows - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
OPERATING ACTIVITIES:
Net income (loss)	$ 13,715,000	$ (99,407,000)	$ 10,163,000
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	14,734,000	11,747,000	9,980,000
Provision for bad debt	394,000	610,000	291,000
Stock-based compensation expense	3,339,000	47,281,000	5,132,000
Gain on sale of assets held for sale and other	(4,503,000)	(244,000)	35,000
Impairment of intangible assets	608,000	0	0
Deferred income taxes	763,000	52,571,000	(6,076,000)
Other, net	(183,000)	542,000	230,000
Changes in assets and liabilities:
Accounts receivable	(1,394,000)	(10,397,000)	(4,397,000)
Prepaid expenses and other current assets	204,000	1,559,000	(2,337,000)
Other long-term assets	(1,660,000)	(11,288,000)	(930,000)
Accounts payable	1,647,000	(1,087,000)	(1,321,000)
Accrued compensation and benefits	5,678,000	2,060,000	2,366,000
Other accrued expenses and current liabilities	(6,667,000)	6,207,000	(1,173,000)
Deferred revenue	9,555,000	15,937,000	9,422,000
Net cash provided by operating activities	36,230,000	16,091,000	21,385,000
INVESTING ACTIVITIES:
Payments for acquisition of businesses, net of cash acquired	(203,438,000)	(15,582,000)	(6,499,000)
Capital expenditures	(6,659,000)	(7,522,000)	(9,444,000)
Proceeds from sale of assets held for sale and other	6,614,000	446,000	34,000
Payments for acquisition of developed technology	(2,727,000)	(2,120,000)	(154,000)
Other investing activities, net		(73,000)	30,000
Net cash used in investing activities	(206,210,000)	(24,851,000)	(16,033,000)
FINANCING ACTIVITIES:
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	37,041,000	126,832,000	151,928,000
Payments on revolving commitment	(6,091,000)	(154,187,000)	(136,087,000)
Proceeds from issuance of common stock	2,077,000	1,792,000	456,000
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)	(16,232,000)
Payments for redemption of common stock	(119,000)	(1,045,000)	(3,049,000)
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	2,030,000
Payment for return of capital			(725,000)
Other financing activities	(268,000)	(130,000)	(185,000)
Net cash provided by (used in) financing activities	167,530,000	29,558,000	(1,864,000)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(1,443,000)	1,641,000	(362,000)
Net (decrease) increase in cash, cash equivalents and restricted cash	(3,893,000)	22,439,000	3,126,000
Cash, cash equivalents and restricted cash at beginning of year	39,578,000	17,139,000	14,013,000
Cash, cash equivalents and restricted cash at end of period	35,685,000	39,578,000	17,139,000
Supplemental disclosures of cash flow:
Interest paid	223,000	2,092,000	2,190,000
Income taxes paid	6,735,000	5,893,000	5,909,000
Supplemental disclosure of non-cash investing and financing activities:
Issuance of common stock in connection with acquisitions	8,681,000	8,712,000
Promissory notes issued and deferred payment obligations for acquisitions	1,729,000	12,352,000	4,182,000
Capital leases	895,000	124,000	129,000
Property and equipment in accounts payable, other accrued expenses and current liabilities, and other liabilities	$ 330,000	582,000	1,777,000
Issuance of common stock with put rights		2,352,000
Initial public offering costs in accounts payable		$ 186,000
Notes issued for stock redemptions			$ 807,000

Description of Business

Description of Business	12 Months Ended
	Dec. 31, 2018
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 intelligence. 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 intelligence and true-to-life visualization and rendering. Altair’s software products represent a comprehensive, open architecture solution for simulation, data intelligence 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.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of significant accounting policies 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 2017 and 2016 consolidated statements of cash flows have been reclassified to conform to the current year presentation. Specifically, in the accompanying consolidated statement of cash flows for the years ended December 31, 2017 and 2016, Gain on sale of assets held for sale and other has been reclassified out of Other operating activities. This reclassification had no effect on Net cash provided by operating activities. Additionally, Proceeds from the sale of assets held for sale and other has been reclassified out of Other investing activities. This reclassification had no effect on Net cash used in investing activities. 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 determination of the period of benefit for capitalized costs to obtain a contract, 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 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 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 recent 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. 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 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. Deferred revenue Deferred revenue consists of customer billings or payments received in advance of the recognition of revenue and is recognized as revenue when revenue recognition criteria are met. 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, 2018 2017 Cash and cash equivalents $ 35,345 $ 39,213 Restricted cash included in other long-term assets 340 365 Total cash, cash equivalents, and restricted cash shown in the statement of cash flows $ 35,685 $ 39,578 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 consisted of the following (in thousands): December 31, 2018 2017 Accounts receivable, trade $ 93,073 $ 82,185 Contract assets 3,730 4,450 Accounts receivable, net $ 96,803 $ 86,635 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 $1.2 million and $0.8 million at December 31, 2018 and 2017, respectively. Activity in the allowance for doubtful accounts was as follows (in thousands): For the year ended December 31, 2018 2017 2016 Balance, beginning of year $ (798 ) $ (565 ) $ (937 ) Provision charged to expense (394 ) (610 ) (291 ) Write-offs, net of recoveries 3 414 638 Effects of foreign currency translation 39 (37 ) 25 Balance, end of year $ (1,150 ) $ (798 ) $ (565 ) 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 45%, 50%, and 50% of the Company’s 2018, 2017 and 2016 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, 2018, 2017 or 2016. 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. 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 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 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 2018, 2017, or 2016. 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, 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 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 it is determined that the estimated fair value of the reporting unit is more likely than not less than its carrying amount, including goodwill, the two-step goodwill impairment test is required. Otherwise, no further analysis would be required. For 2017 and 2016, 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 may skip the qualitative assessment, or if the two-step impairment test for goodwill is deemed necessary, this quantitative impairment analysis compares the fair value of the Company’s reporting unit to its related carrying value. If the fair value of the reporting unit exceeds its carrying amount, step two does not need to be performed. If the fair value of the reporting unit is less than its carrying amount, an indication of goodwill impairment exists and the Company must perform step two of the impairment test. Under step two, an impairment loss is recognized for any excess of the carrying amount of the reporting unit’s goodwill over the implied fair value of that goodwill. The implied fair value of goodwill is determined by allocating the fair value of the reporting unit in a manner similar to a purchase price allocation and the residual fair value after this allocation is the implied fair value of the reporting unit goodwill. Fair value of the reporting units is determined using an income approach. The income approach is based on projected debt-free cash flows which are discounted to the present value using discount factors that consider the timing and risk of cash flows. The Company also takes into consideration a multiple of earnings valuation technique. The Company believes that this approach is appropriate because it provides a reasonable estimate of the price that would be received to sell the reporting unit in an orderly transaction between market participants at the measurement date. While there are inherent uncertainties related to the assumptions used in this analysis, the Company believes that this approach provides a reasonable estimate of fair value. 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. During the quarter ended September 30, 2018, the Company performed an interim 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. Three was no indication of impairment of other indefinite-lived intangible assets for the Company’s annual test which is completed in the fourth quarter. No impairment charges were recognized in 2017 and 2016. 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, 2018, the Company had approximately $11.7 million receivable from the French government related to CIR, of which $2.6 million is recorded in income tax receivable and the remaining $9.1 million is recorded in other long-term assets. As of December 31, 2017, the Company had approximately $10.2 million receivable from the French government related to CIR, of which $3.3 million was recorded in income tax receivable and the remaining $6.9 million was recorded in other long-term assets. CIR is subject to customary audit by the French tax authorities. Valuation of common stock prior to IPO Due to the absence of an active market for the Company’s common stock prior to the Company’s IPO in the fourth quarter of 2017, the Board of Directors, with the assistance of a third-party valuation specialist, determined the fair value of the Company’s common stock. The valuation methodology included estimates and assumptions including forecasts of future cash flows that required significant judgments. These valuations considered a number of objective and subjective factors, including the Company’s actual operating and financial performance, external market conditions, performance of comparable publicly traded companies, comparable transactions, business developments, likelihood of achieving a liquidity event, such as an initial public offering or sale, and common stock transactions, among other factors. The Company utilized methodologies in accordance with the framework of the American Institute of Certified Public Accountants’ Technical Practice Aid, Valuation of Privately-Held Company Equity Securities issued as Compensation, 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 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 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 $97.6 million, $93.2 million, and $71.3 million for the years ended December 31, 2018, 2017 and 2016, respectively. Advertising costs Advertising costs are expensed as incurred. Advertising expenses were $4.4 million, $3.5 million and $2.5 million for the years ended December 31, 2018, 2017, and 2016, respectively. 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, 2018, the classification remains as mezzanine equity. 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 the quarter ended June 30, 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 in the fourth quarter of 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. Recent accounting guidance Accounting standards adopted The Company ceased to qualify as an emerging growth company (as defined in the Jumpstart Our Business Startups Act of 2012) as of December 31, 2018, therefore all of the 2018 public company adoptions are reflected in this Annual Report on Form 10-K. Revenue Recognition —In May 2014, the Financial Accounting Standards Board, or “FASB”, issued ASU No. 2014-09, (ASU 2014-09)

Revenue from Contracts with Cus

Revenue from Contracts with Customers	12 Months Ended
	Dec. 31, 2018
Revenue From Contract With Customer [Abstract]
Revenue from Contracts with Customers	3. Revenue from contracts with customers 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 are allowed in the application of this new guidance. The Company recorded a decrease to accumulated deficit of $84.6 million, or $70.8 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. 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 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 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. 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 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. Impact of ASC 606 on consolidated financial statement line items The following table summarizes the cumulative impact of adoption of the new revenue standard for revenue recognition on line items within the consolidated balance sheets (in thousands): As of December 31, 2017 Prior to adoption of ASC 606 Adjustments for ASC 606 As Adjusted Prepaid expenses and other current assets $ 10,006 $ 1,589 $ 11,595 Deferred tax assets $ 8,351 $ (12,352 ) $ (4,001 ) Other long-term assets $ 17,019 $ 128 $ 17,147 Other accrued expenses and current liabilities $ 21,744 $ 1,049 $ 22,793 Deferred revenue, current $ 130,122 $ (77,645 ) $ 52,477 Deferred revenue, non-current $ 9,640 $ (5,263 ) $ 4,377 Other long-term liabilities $ 17,647 $ 445 $ 18,092 Accumulated deficit $ (166,499 ) $ 70,779 $ (95,720 ) As of December 31, 2018 Prior to adoption of ASC 606 Adjustments for ASC 606 As Reported Prepaid expenses and other current assets $ 13,693 $ 1,798 $ 15,491 Deferred tax assets $ 14,092 $ (12,719 ) $ 1,373 Other long-term assets $ 17,077 $ 211 $ 17,288 Other accrued expenses and current liabilities $ 25,435 $ 912 $ 26,347 Deferred revenue, current $ 144,710 $ (84,945 ) $ 59,765 Deferred revenue, non-current $ 13,791 $ (7,037 ) $ 6,754 Other long-term liabilities $ 27,636 $ 517 $ 28,153 Accumulated deficit $ (163,600 ) $ 81,595 $ (82,005 ) Accumulated other comprehensive loss $ (9,300 ) $ (1,752 ) $ (11,052 ) 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 accelerates 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. This change in the pattern of revenue recognition, coupled with the recording of deferred revenue to accumulated deficit as of January 1, 2018, resulted in the changes to the consolidated balance sheet line items as noted in the table above. 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 $ 12,472 $ 837 $ 13,309 Net income $ 2,899 $ 10,816 $ 13,715 Income per share: Basic $ 0.04 $ 0.16 $ 0.20 Diluted $ 0.04 $ 0.14 $ 0.18 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 adoption of ASC 606 had no impact on the Company’s cash flows from operations. However, with the adoption of ASC 606, there will be an acceleration of income tax payments associated with deferred revenue credited to accumulated deficit and never recognized as revenue in the financial statements. The 2019 tax payments related to the adoption of ASC 606 is expected to be approximately $1.0 million. 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, 2018 (ASC 606) 2017 (ASC 605) (1) 2016 (ASC 605) (1) Software revenue: Term licenses $ 168,909 Perpetual licenses 38,255 Maintenance 86,150 Professional services and other 11,047 Total software revenue $ 304,361 $ 244,817 $ 223,818 (1) As noted above, prior period amounts have not been adjusted under the modified retrospective approach. Under ASC 606, the Company derived approximately10% of its total revenue through indirect sales channels for the year ended December 31, 2018. For the year ended December 31, 2018, software related services revenue of $36.9 million, client engineering services of $47.9 million and other revenue of $7.2 million, were categorized based on the nature, timing and uncertainty of revenue and cash flows effected by economic factors. 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, 2018, capitalized costs to obtain a contract were $2.0 million recorded in Prepaid and other current assets and $0.2 million recorded in Other long-term assets. Amortization expense was $0.3 million for the year ended December 31, 2018 and is included in sales and marketing expense in the Company’s consolidated 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. Approximately $53.0 million of revenue was recognized during 2018 was included in the deferred revenue balances at the beginning of the year.

Acquisitions

Acquisitions	12 Months Ended
	Dec. 31, 2018
Business Combinations [Abstract]
Acquisitions	4. Acquisitions 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. Datawatch provides data intelligence technologies with market leading enterprise data preparation, predictive analytics and visualization solutions that fuel business analytics. Datawatch’s products include software applications known as Monarch, Knowledge Studio and Panopticon. The data intelligence markets are evolving rapidly to leverage many of the same technologies, such as high-performance computing and visualization. Datawatch’s solutions, which include data preparation, data prediction, and real-time high-volume data visualization technologies, are highly relevant and applicable to almost any company and vertical market, including many of the industry segments currently using Altair’s technology. The Company intends to cross-sell Datawatch products into Altair’s diversified global customer base. Pursuant to the Merger Agreement, the Purchaser commenced a tender 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. As a result of the merger, subject to certain potential exceptions provided for in the merger agreement, all remaining shares of Datawatch common stock not previously tendered into Altair’s tender offer were converted into the right to receive $13.10 per share in cash, without interest and less any applicable withholding taxes. 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 following table summarizes the preliminary 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 10,784 Other assets 3,055 Property and equipment 980 Trade names 7,400 Developed technology (6-year life) 22,600 Customer relationships (10-year life) 16,400 Accounts payable and other liabilities (5,393 ) Deferred revenue (4,100 ) Other long-term liabilities (7,928 ) Total net identifiable assets acquired and liabilities assumed 52,076 Goodwill (1) $ 131,351 (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 preliminary fair value of net tangible and identifiable intangible assets acquired was recorded as goodwill. The preliminary fair values assigned to tangible and identifiable intangible assets acquired and liabilities assumed are based on management’s estimates and assumptions. The deferred tax liability established was primarily a result of the difference in the book basis and tax basis related to the identifiable intangible assets. The preliminary estimated fair values of assets acquired and liabilities assumed, including current and noncurrent income taxes payable and deferred taxes, customer contract assets and liabilities and identifiable intangible assets may be subject to change as additional information is received and certain tax returns are finalized. Thus, the provisional measurements of fair value set forth above are subject to change. 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. The Company expects to finalize the valuation as soon as practicable, but not later than one year from the acquisition date. Unaudited Pro Forma Financial Information The unaudited pro forma results presented below include the effects of the Datawatch acquisition as if it had been consummated as of January 1, 2017. The pro forma results below include adjustments related to conforming revenue accounting policies, amortization to reflect the fair value of acquired identifiable intangible assets, share-based compensation associated with accelerated vesting, acquisition-related costs, and the associated income tax impacts. The pro forma information does not necessarily reflect the actual results of operations had the acquisition been consummated at the beginning of the fiscal reporting period indicated nor is it indicative of future operating results. The pro forma information does not include any adjustment for (i) potential revenue enhancements, cost synergies or other operating efficiencies that could result from the acquisition or (ii) transaction or integration costs relating to the acquisition. The unaudited pro forma financial information was as follows (in thousands, except per share data): Year ended December 31, 2018 2017 Total revenue $ 435,414 $ 363,906 Net income (loss) $ 7,613 $ (115,010 ) Net income (loss) per share attributable to common stockholders, basic $ 0.11 $ (2.19 ) Net income (loss) per share attributable to common stockholders, diluted $ 0.10 $ (2.19 ) SIMSOLID Corporation In October 2018, the Company acquired all of the outstanding capital stock commitments (through convertible notes and deferred shares) to issue an additional 145,000 shares of the Company’s Class A common stock, one half of which will be issued on the first business day following the one year anniversary of the closing date and one half of which will be issued on the first business day following the two year anniversary of the closing date, subject to acceleration in the event of a change of control of the Company and subject to reduction as a set-off to any indemnification obligations The convertible promissory notes will convert into 41,537 additional shares of the Company’s Class A common stock, which can be converted by either party on the first business day following the one year anniversary of the closing date and on the first business day following the two year anniversary of the closing date, subject to acceleration in the event of a change of control of the Company and subject to reduction as a set-off to any indemnification obligations. The convertible notes are accounted for as other current and non-current liabilities as of December 31, 2018. The shares associated with the convertible notes are excluded from the calculation of basic shares outstanding as of December 31, 2018. The financial results of SIMSOLID have been included in the consolidated financial statements since the acquisition date. SIMSOLID works on full-fidelity computer-aided design, or CAD, assemblies to provide fast, accurate, and robust structural simulation without requiring geometry simplification, cleanup, or meshing. The SIMSOLID computational engine is a commercial implementation of novel and unpublished mathematics based on extensions to the theory of external approximations. SIMSOLID controls solution accuracy using multi-pass adaptive analysis, which the Company believes makes the SIMSOLID solution extremely fast, accurate and memory efficient. The following table summarizes the consideration transferred to acquire SIMSOLID and the amounts of identified assets acquired and liabilities assumed at the acquisition date (in thousands): Fair value of consideration transferred $ 22,139 Recognized amounts of identifiable assets acquired and liabilities assumed: Current assets $ 135 Trade names 344 Developed technology 3,291 Current liabilities (141 ) Long term liabilities (960 ) Total net identifiable assets acquired and liabilities assumed 2,669 Goodwill $ 19,470 The allocation of fair value of purchase consideration is incomplete pending the final determination of the fair value of assets acquired and liabilities assumed, and 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. Goodwill is primarily attributable to market synergies expected to arise after the acquisition and is not deductible for tax purposes. FluiDyna GmbH In May 2018, the Company purchased the remaining equity interests in FluiDyna GmbH (“FluiDyna”) for aggregate consideration of EUR 2.2 million ($2.7 million). Prior to the purchase of the remaining equity interests, the Company owned 24% of the outstanding equity interests in FluiDyna. The purchase price was allocated to assets and liabilities of FluiDyna based on the fair values of the assets acquired and liabilities assumed. The allocation included $2.1 million to intangibles, consisting of developed technology and customer relationships and $1.8 million to goodwill, which is not tax deductible. The financial results of FluiDyna 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. FluiDyna developed NVIDIA CUDA and GPU-based Computational Fluid Dynamics (“CFD”) and numerical simulation technologies. The Company made an initial investment in FluiDyna in 2015. FluiDyna’s simulation software products ultraFluidx and nanoFluidx have been available to the Company’s customers through the Altair Partner Alliance and also offered as standalone licenses. ultraFluidX solves large scale internal and external aerodynamics problems for a broad class of problems including ultra-fast prediction and evaluation of vehicle, building, and environmental aerodynamics. nanoFluidX is a fluid dynamics simulation tool based on the smoothed particle hydrodynamics method to predict the flow in complex geometries with complex motion. CANDI Controls, Inc. In April 2018, the Company entered into an asset purchase agreement with California-based CANDI Controls, Inc. (“CANDI”) and acquired all the intellectual property assets of CANDI for $2.4 million. The sale was approved by the bankruptcy court on April 25, 2018, and the asset purchase was completed on April 26, 2018. CANDI developed a modern platform which supports multiple data protocols for edge gateway computers to communicate with a constellation of Internet of Things (“IoT”) devices. CANDI’s software is designed to easily connect systems and equipment with cloud-based monitoring and control services to help organizations improve performance, conserve resources, and cut operational costs. Sensor data can be analyzed, visualized, and processed with machine learning and predictive analytics tools to forecast performance and prescribe actions consistent with business objectives. Runtime Design Automation On September 28, 2017, the Company acquired 100% of the shares of Runtime Design Automation (“Runtime”) for a total of $19.4 million in cash, of which $9.4 million is payable one year from the acquisition date, which includes a $0.7 million working capital adjustment, and 708,000 shares of the Company’s Class A common stock. Runtime complements Altair’s PBS Works™ suite of products for comprehensive, secure workload management for HPS and cloud environments and has solutions to manage highly complex workflows. PBS Works targets product design, weather prediction, oil exploration and bio-informatics, and Runtime primarily serves customers in electronic design automation. The following table summarizes the consideration transferred to acquire Runtime and the amounts of identified assets acquired and liabilities assumed at the acquisition date (in thousands): Fair value of consideration transferred $ 25,508 Recognized amounts of identifiable assets acquired and liabilities assumed: Cash 564 Accounts receivable 2,257 Deferred tax assets 1,713 Other assets 257 Trade names 440 Developed technology (4-year life) 7,870 Customer relationships (7-year life) 2,490 Accounts payable and other liabilities (1,000 ) Deferred revenue (1,925 ) Deferred tax liabilities (4,645 ) Total net identifiable assets acquired and liabilities assumed 8,021 Goodwill $ 17,487 Goodwill is primarily attributable to market synergies expected to arise after the acquisition and is not deductible for tax purposes. Carriots S.L. In May 2017, the Company acquired 100% of the shares of Carriots S.L. (“Carriots”) for $3.6 million cash, $2.7 million notes payable, and 80,000 shares of the Company’s Class A common stock. Carriots is an Internet of Things (“IoT”) Cloud platform that allows easy development of new IoT enabled products. Carriots complements Altair’s other product suites to provide a comprehensive solution for customers to design and implement IoT enabled products. The following table summarizes the consideration transferred to acquire Carriots and the amounts of identified assets acquired and liabilities assumed at the acquisition date (in thousands): Fair value of consideration transferred $ 6,657 Recognized amounts of identifiable assets acquired and liabilities assumed: Deferred tax assets 394 Other assets 472 Trade names 252 Developed technology (4-year life) 1,317 Customer relationships (7-year life) 296 Accounts payable and other liabilities (1,015 ) Total net identifiable assets acquired and liabilities assumed 1,716 Goodwill $ 4,941 Goodwill is primarily attributable to market synergies expected to arise after the acquisition and is not deductible for tax purposes. Other business acquisitions During the year ended December 31, 2017, 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. The combined purchase price related to the 2017 acquisitions, excluding Runtime and Carriots, was not material. For each of its acquisitions the Company engaged a third-party valuation firm to assist the Company in valuing certain assets and liabilities acquired.

Property and Equipment, Net

Property and Equipment, Net	12 Months Ended
	Dec. 31, 2018
Property Plant And Equipment [Abstract]
Property and Equipment, Net	5. Property and equipment, net Property and equipment consisted of the following (in thousands): Estimated December 31, useful lives 2018 2017 Land Indefinite $ 7,994 $ 7,994 Building and improvements 5-39 years 13,120 15,185 Computer equipment and software 3-5 years 34,582 32,103 Office furniture and equipment 5-15 years 7,958 6,751 Leasehold improvements (1 ) 6,926 6,467 Total property and equipment 70,580 (2) 68,500 (2) Less: accumulated depreciation and amortization 40,427 37,054 Property and equipment, net $ 30,153 $ 31,446 (1) Shorter of lease term or estimated useful life, generally ranging from five to ten years. (2) Equipment under capital lease obligations had an original carrying value of approximately $2.0 million and $1.1 million at December 31, 2018 and 2017, respectively. On August 7, 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. In November 2016, the Company purchased land adjacent to Altair’s corporate headquarters for $4.0 million for future expansion of the Company’s facilities. Depreciation expense, including amortization of assets under capital lease, was $7.0 million, $6.3 million and $6.7 million for the years ended December 31, 2018, 2017 and 2016, respectively.

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	12 Months Ended
	Dec. 31, 2018
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, 2016 $ 36,625 Acquisitions 22,420 Effects of foreign currency translation 3,661 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 Other intangible assets A summary of other intangible assets is shown below (in thousands): 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 December 31, 2017 Weighted average amortization period Gross carrying amount Accumulated amortization Net carrying amount Definite-lived intangible assets: Developed technology 4 years $ 25,947 $ 9,909 $ 16,038 Customer relationships 7 years 11,794 6,195 5,599 Other intangibles 10 years 143 57 86 Total definite-lived intangible assets 37,884 16,161 21,723 Indefinite-lived intangible assets: Trade names 2,738 2,738 Total other intangible assets $ 40,622 $ 16,161 $ 24,461 Amortization expense related to amortizing intangible assets was $7.7 million, $5.4 million and $3.3 million for the years ended December 31, 2018, 2017 and 2016, respectively. Estimated amortization expense for the next five years as of December 31, 2018 is as follows (in thousands): Year ending December 31, 2019 $ 13,880 December 31, 2020 $ 12,959 December 31, 2021 $ 10,590 December 31, 2022 $ 7,378 December 31, 2023 $ 6,627

Debt

Debt	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Debt	7. Debt The carrying value of debt is as follows (in thousands): December 31, 2018 2017 Revolving credit facility $ 30,950 $ — Obligations held under capital leases (Note 19) 813 207 Other borrowings 75 203 Total debt 31,838 410 Less: unamortized debt issuance costs 90 — Less: current portion of long-term debt 331 232 Long-term debt, net of current portion $ 31,417 $ 178 Credit agreement Revolving credit facility On October 18, 2017, the Company entered into an amended and restated credit agreement with Altair Engineering Inc., as borrower, JPMorgan Chase Bank, N.A., as the lead arranger, sole book runner, the administrative agent, swingline lender and letter of credit issuer, and a syndicate of lenders (“2017 Credit Agreement”). The 2017 Credit Agreement provided for an initial aggregate commitment amount of $100.0 million, with a sublimit for the issuance of letters of credit of up to $5.0 million and a sublimit for swingline loans of up to $5.0 million. The 2017 Credit Agreement matures on October 18, 2022. The 2017 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 2017 Credit Agreement). On October 31, 2018, the Company increased the revolving commitment available under the 2017 Credit Agreement from $100.0 million to $150.0 million. There were no other material changes to the terms of the 2017 Credit Agreement. As of December 31, 2018, the Company had $31.0 million of outstanding borrowings under the 2017 Credit Agreement and there was $119.0 million available for future borrowing. The 2017 Credit Agreement is available for general corporate purposes, including working capital, capital expenditures, and permitted acquisitions. The weighted average interest rate on borrowings under the 2017 Credit Agreement was 4.6% for the year ended December 31, 2018. Borrowings under the 2017 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 2017 Credit Agreement) in effect on such day, (2) the Federal Funds Effective Rate (as defined in the 2017 Credit Agreement) in effect on such day plus 1/2 of 1.00% or (3) the Adjusted LIBO Rate (as defined in the 2017 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 2017 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 2017 Credit Agreement. Collateral and guarantees The 2017 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 2017 Credit Agreement). The Company’s direct and indirect domestic subsidiaries are guarantors of all the obligations under the 2017 Credit Agreement. Debt covenants The 2017 Credit Agreement requires the Company to maintain the following financial covenants: • Maximum Net Leverage Ratio : Commencing with the fiscal quarter ending December 31, 2017 and on the last day of each fiscal quarter thereafter, 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 2017 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 : Commencing with the fiscal quarter ending December 31, 2017 and on the last day of each fiscal quarter thereafter, 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 2017 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, 2018, the Company was in compliance with all such financial covenants. Prior credit agreement Prior to entering into the 2017 Credit Agreement, the Company’s credit agreement consisted of a $65.0 million term loan and a $60.0 million revolving commitment, including a $5.0 million swingline subfacility, and a letter of credit subfacility (collectively, the “Secured Credit Agreement”.) At December 31, 2016, the Company had $84.9 million outstanding under the Secured Credit Agreement and there was $32.6 million available for future borrowing. All borrowings under the Secured Credit Agreement were due on the termination date in April 2019. On November 3, 2017, in connection with the completion of the Company’s IPO, the Company repaid in full all outstanding debt under the Secured Credit Agreement. The Company paid a total of approximately $93.1 million, which included outstanding principal, interest, and other nominal costs. Upon the repayment of the Secured Credit Agreement, all unamortized debt issuance costs were recorded as interest expense. 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, 2018 and 2017, the Company had $3.5 million of availability under these facilities and there were no outstanding commitments. Scheduled maturities of long-term debt At December 31, 2018, future maturities of long-term debt, excluding capital leases, were as follows (in thousands): Year ending December 31, 2019 $ 75 2020 — 2021 — 2022 30,950 2023 — Total $ 31,025

Other Liabilities

Other Liabilities	12 Months Ended
	Dec. 31, 2018
Other Liabilities Disclosure [Abstract]
Other Liabilities	8. Other liabilities The following table provides the details of other accrued expenses and current liabilities (in thousands): December 31, 2018 2017 Accrued VAT $ 4,536 $ 3,916 Income taxes payable 4,458 3,724 Accrued professional fees 3,165 2,500 Accrued royalties 2,613 2,037 Billings in excess of cost 1,504 832 Defined contribution plan liabilities 1,376 1,274 Government grants 915 712 Non-income tax liabilities 853 1,343 Related party liabilities — 119 Other current liabilities 6,927 5,287 Total $ 26,347 $ 21,744 The following table provides the details of other long-term liabilities (in thousands): December 31, 2018 2017 Pension and other post retirement liabilities $ 9,111 $ 7,670 Deferred tax liabilities 7,736 1,620 Other liabilities 11,306 8,357 Total $ 28,153 $ 17,647

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	9. 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. Items measured at fair value on a recurring basis The following table sets forth a summary of the changes in the fair value of the Company’s Level 3 financial liabilities (in thousands): Liability for Class A redeemable common shares Liability for stock-based compensation awards Balance at December 31, 2016 $ 10,632 $ 11,604 Exercise of stock options 432 (411 ) Forfeitures of stock options — (157 ) Change in fair value 19,223 25,191 Modification to stock options as a result of the Company’s IPO (1) (30,287 ) (36,227 ) Balance at December 31, 2017 $ — $ — (1) As a result of the Company’s IPO in the fourth quarter of 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 in the fourth quarter of 2017 in accordance with ASC 718. 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 10—Financial instruments for additional information regarding the use and fair value of derivatives.

Financial Instruments

Financial Instruments	12 Months Ended
	Dec. 31, 2018
Investments All Other Investments [Abstract]
Financial Instruments	10. 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, 2018, and 2017, the Company had an interest rate swap outstanding with a $4.5 million notional value. This interest rate swap matures 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, 2018 or 2017. Derivative instruments As of December 31, 2018 and 2017, the fair value of the Company’s derivative instruments included in other long-term liabilities was a liability of $0.1 million and $0.2 million, respectively. 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. As of December 31, 2018, the Company had not and was not required to post any collateral to support its derivatives in a liability position.

Stockholders_ Equity

Stockholders’ Equity	12 Months Ended
	Dec. 31, 2018
Equity [Abstract]
Stockholders' Equity	11. Stockholders’ equity Preferred stock As of December 31, 2018, 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, 2018, 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 2018, 2017 or 2016.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	12. 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 4,337,856 stock options with an exercise price of $.000025 remain outstanding at December 31, 2018. 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, 2018 6,441,972 $ 0.000025 19.0 $ 154.1 Exercised (2,104,116 ) $ 0.000025 Forfeited — $ — Outstanding and exercisable at December 31, 2018 4,337,856 $ 0.000025 18.0 $ 119.6 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, 2018 and 2017, there were 532,220 and 888,864 options outstanding, respectively, under the ISO Plan. Until the effective date of the Company’s IPO, options granted under the ISO Plan were accounted for as liability awards as the terms of the awards could require or allow repurchase of the shares at amounts different than fair value. The Company made the accounting policy election to use the intrinsic value method of accounting to determine stock-based compensation liabilities for these awards. During the quarter ended June 30, 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. 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, 2018 888,864 $ 0.67 2.5 $ 20.7 Exercised (356,644 ) $ 0.69 Forfeited — $ — Outstanding and exercisable at December 31, 2018 532,220 $ 0.65 1.4 $ 14.3 The total intrinsic value of the ISO Plan stock options exercised during the years ended December 31, 2018, 2017 and 2016 was $5.2 million, $25.6 million, and $2.7 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 $0.6 million, $0.7 million and $0.6 million for the years ended December 31, 2018, 2017 and 2016, 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, 2018 2,183,127 $ 3.74 7.3 $ 44.1 Granted — $ — Exercised (623,119 ) $ 2.76 Forfeited (18,843 ) $ 4.68 Outstanding at December 31, 2018 1,541,165 $ 4.12 6.9 $ 36.2 Exercisable at December 31, 2018 975,291 $ 3.70 6.1 $ 23.3 Total compensation cost related to nonvested awards not yet recognized as of December 31, 2018 totaled $0.9 million and is expected to be recognized over a weighted average period of 2.7 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, 2018 — Granted 228,201 Vested (1,000 ) Forfeited (21,140 ) Outstanding at December 31, 2018 206,061 The weighted average grant date fair value of the RSUs was $30.96 and the RSUs generally vest in four equal annual installments. Total compensation cost related to nonvested awards not yet recognized as of December 31, 2018, totaled $5.3 million, and is expected to be recognized over a weighted average period of four years. 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 weighted average assumptions used in the Black-Scholes option pricing model used to calculate the fair value of options granted during the years ended December 31, 2017 and 2016 are as follows: 2017 grants 2016 grants Weighted average grant date fair value per share $1.86 - $1.94 $1.42 - $1.65 Expected volatility 34 % 37 % Expected term (in years) 5.75-6.25 5.75-6.25 Risk-free interest rate 2.02 % 1.37%-1.79% Expected dividend yield 0 % 0 % Prior to the IPO, the Company’s equity value was estimated utilizing a combination of the Discounted Cash Flow Method under the Income Approach, the Guideline Public Company Method, and the Transaction Method under the Market Approach. The equity value is used to derive the fair value per share which is used as an input in the Black Scholes option pricing model. The estimated volatility was derived using the historical volatility of the returns of comparable publicly traded companies. The risk-free rate was based on U.S. Treasury zero-coupon yield curves with a remaining term equal to the expected term of the option. The Company has not historically paid dividends and does not anticipate paying cash dividends in the foreseeable future. The Company used the simplified method to determine expected term. Other 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 2.0 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, 2018, was $0.6 million 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, 2018 2017 2016 Cost of revenue-software $ 31 $ 350 $ 22 Research and development 740 12,540 1,370 Sales and marketing 910 7,693 775 General and administrative 1,658 26,698 2,965 Total stock-based compensation expense $ 3,339 $ 47,281 $ 5,132

Other (Income) Expense, Net

Other (Income) Expense, Net	12 Months Ended
	Dec. 31, 2018
Other Income And Expenses [Abstract]
Other (Income) Expense, Net	13. Other (income) expense, net Other (income) expense, net consists of the following (in thousands): Year ended December 31, 2018 2017 2016 Foreign exchange (gain) loss $ (626 ) $ 1,254 $ (271 ) Other (1,954 ) (260 ) (249 ) Other (income) expense, net $ (2,580 ) $ 994 $ (520 )

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	14. Income taxes The components of income (loss) before income taxes are as follows (in thousands): Year ended December 31, 2018 2017 2016 U.S. $ 4,228 $ (49,761 ) $ (2,225 ) Non-U.S. 22,796 13,350 15,927 $ 27,024 $ (36,411 ) $ 13,702 The significant components of the income tax expense are as follows (in thousands): Year ended December 31, 2018 2017 2016 Current U.S. Federal $ 2 $ — $ — Non-U.S. 12,552 10,290 9,413 U.S. State and Local (8 ) 135 202 Total current 12,546 10,425 9,615 Deferred U.S. Federal 1,714 54,130 (5,358 ) Non-U.S. (934 ) (1,306 ) (610 ) U.S. State and Local (17 ) (253 ) (108 ) Total deferred 763 52,571 (6,076 ) Income tax expense $ 13,309 $ 62,996 $ 3,539 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, 2018 2017 2016 U.S. federal statutory rate 21 % 35 % 35 % Income taxes at U.S. federal statutory rate $ 5,675 $ (12,744 ) $ 4,796 Foreign income taxes at rates other than the federal statutory rate 2,096 373 (584 ) U.S. state and local income taxes, net of U.S. federal tax benefit (3,446 ) (155 ) 94 U.S. Tax Cut and Jobs Act: transition tax, net of foreign tax credits — 4,187 — Global intangible low-taxed income 6,587 — — Change in valuation allowance 16,725 47,429 — Foreign withholding taxes 5,103 4,181 4,235 Foreign dividends — — 5,077 U.S. foreign tax credit (4,564 ) (4,154 ) (8,786 ) Research and development tax credit (2,819 ) (2,999 ) (2,696 ) Domestic production activities deduction — — (840 ) Non-deductible stock-based compensation (14,964 ) 10,871 2,064 Meals & entertainment 181 358 235 Other 672 (163 ) (91 ) Deferred tax on investment in subsidiary — — (264 ) Uncertain tax positions 903 446 299 Acquisition costs 503 — — Tax law changes 657 15,366 — Income tax expense $ 13,309 $ 62,996 $ 3,539 The Tax Cuts and Jobs Act, or the Tax Act, was enacted on December 22, 2017. The Tax Act reduces the U.S. federal corporate income tax rate from 35% to 21%, requires companies to pay a one-time transition tax on earnings of certain foreign subsidiaries that were previously tax deferred and creates new taxes on certain foreign sourced earnings. The Company is applying 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 has completed its accounting for the tax effects of the Tax Act; the Company has not recorded 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. 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, 2018 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, 2018 2017 Deferred tax assets: Deferred revenue $ 3,063 $ 19,569 Net operating loss carryforwards 37,549 7,601 Tax credit carryforwards 30,516 22,191 Stock-based compensation 6,858 8,922 Capitalized research and development 8,266 8,798 Accrued expenses — 648 Employee benefits 4,825 3,931 Other 1,777 1,905 Total gross deferred tax assets 92,854 73,565 Less: valuation allowances (76,101 ) (54,331 ) Net deferred tax assets (1) 16,753 19,234 Deferred tax liabilities: Prepaid royalties 7,687 6,925 Property and equipment and intangibles 13,945 4,567 Deferred tax on investment in subsidiary 329 272 Other 1,155 739 Total deferred tax liabilities 23,116 12,503 Total net deferred tax assets $ (6,363 ) $ 6,731 (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 • 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, 2018, 2017 and 2016 (in thousands): December 31, 2018 2017 2016 Beginning balance $ 54,331 $ 4,153 $ 2,452 Additions charged to expense 16,725 47,429 177 Deductions — — (207 ) Other 5,045 2,749 1,731 Ending balance $ 76,101 $ 54,331 $ 4,153 The amount in Other for 2018 of $5.0 million is primarily related to the recording of a valuation allowance against deferred taxes recorded for business combinations of $12.6 million, and to accumulated deficit related to the adoption of ASC 606 for $(7.4) million. The following table summarizes the amount and expiration dates of operating loss and tax credit carryforwards at December 31, 2018 (in thousands): Expiration dates Amounts U.S. general business credits and loss carryforwards 2019-Indefinite $ 53,853 Foreign loss carryforwards Indefinite 8,030 U.S. foreign tax credits 2028 6,182 Total operating loss and tax credit carryforwards $ 68,065 A reconciliation of the beginning and ending amounts of unrecognized tax benefits is as follows (in thousands): Year ended December 31, 2018 2017 2016 Unrecognized tax benefits—January 1 $ 6,157 $ 5,604 $ 5,305 Increase in unrecognized tax benefits as a result of: Additions for tax positions of current period 234 634 299 Additions for tax positions of prior periods 10,866 — — Reductions for tax positions of prior periods (100 ) (81 ) — Reductions due to statute of limitations (60 ) — — Unrecognized tax benefits—December 31 $ 17,097 $ 6,157 $ 5,604 At December 31, 2018, the Company had $17.1 million of gross unrecognized tax benefits that if recognized would affect the effective tax rate and adjustments to other tax accounts, primarily deferred taxes. The Company expects a change in the gross unrecognized tax benefits to be approximately $0.4 million that will impact the effective tax rate during 2019. 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 2017. All other significant jurisdictions have open tax years from 2014 through 2017. 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, 2018 and 2017, accrued interest and penalties related to unrecognized tax benefits were insignificant.

Income (Loss) Per Share

Income (Loss) Per Share	12 Months Ended
	Dec. 31, 2018
Earnings Per Share [Abstract]
Income (Loss) Per Share	15. Income (loss) per share Basic income (loss) 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. Diluted income (loss) 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 under the treasury stock method. The following table sets forth the computation of the numerators and denominators used in the basic and diluted income (loss) per share amounts (in thousands, except per share data): Year ended December 31, 2018 2017 2016 Numerator: Net income (loss) $ 13,715 $ (99,407 ) $ 10,163 Denominator: Denominator for basic income (loss) per share— weighted average shares 67,468 52,466 48,852 Effect of dilutive securities, stock options and RSUs 7,410 — 9,004 Denominator for dilutive income (loss) per share 74,878 52,466 57,856 Net income (loss) per share attributable to common stockholders, basic $ 0.20 $ (1.89 ) $ 0.21 Net income (loss) per share attributable to common stockholders, diluted $ 0.18 $ (1.89 ) $ 0.18 The computation of diluted income (loss) 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. For the year ended December 31, 2018, there were no anti-dilutive shares, which were excluded from the computation of income (loss) 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 income (loss) per share. For the year ended December 31, 2016, there were no anti-dilutive shares excluded from the computation of income (loss) per share.

Retirement Benefits

Retirement Benefits	12 Months Ended
	Dec. 31, 2018
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 $1.3 million, $1.1 million and $1.1 million for the years ended December 31, 2018, 2017 and 2016, 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 $1.2 million, $1.2 million and $0.9 million in 2018, 2017 and 2016, respectively. The amount of benefits paid under these plans was $0.4 million, $0.2 million and $0.2 million in 2018, 2017 and 2016, respectively. The accumulated benefit obligation, unlike the projected benefit obligation, does not reflect expected benefit increases from future salary levels, and was $6.0 million and $5.5 million at December 31, 2018 and 2017, respectively, under these plans. The projected benefit obligation, net of plan assets of $0.9 million, was $9.6 million and $8.0 million at December 31, 2018 and 2017, respectively. A summary of the components of the pension benefits obligation recorded in the consolidated balance sheets are as follows (in thousands): December 31, 2018 2017 Accrued compensation and benefits $ 513 $ 368 Other long-term liabilities 9,111 7,670 $ 9,624 $ 8,038 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, 2019 $ 537 December 31, 2020 $ 356 December 31, 2021 $ 283 December 31, 2022 $ 337 December 31, 2023 $ 519 Next five years $ 2,484

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	12 Months Ended
	Dec. 31, 2018
Equity [Abstract]
Accumulated Other Comprehensive Loss	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, 2015 $ (5,745 ) $ (963 ) $ (6,708 ) Other comprehensive income (loss) before reclassification 80 (771 ) (691 ) Tax effects (60 ) 195 135 Other comprehensive income (loss) 20 (576 ) (556 ) 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 (5,211 ) 90 (5,121 ) Amounts reclassified from accumulated other comprehensive loss — (1,177 ) (1,177 ) Tax effects — 318 318 Other comprehensive income (loss) (5,211 ) (769 ) (5,980 ) Balance at December 31, 2018 $ (8,585 ) $ (2,467 ) $ (11,052 )

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2018
Related Party Transactions [Abstract]
Related Party Transactions	18. Related party transactions In February 2017, the Company purchased the noncontrolling interest in a consolidated subsidiary from a founder stockholder for an aggregate purchase price of $29 thousand. In 2016, the Company redeemed 546,776 shares of Class A common stock from related parties for an aggregate purchase price of $2.1 million payable in installments. In 2016, the Company redeemed 113,388 shares of Class B common stock from a founder stockholder for an aggregate purchase price of $0.6 million payable in nine equal monthly installments. In October 2015, the Company acquired Altair Bellingham, LLC from significant stockholders of the Company for cash of $0.7 million, which was paid in February 2016. At December 31, 2018, the Company had no obligations to related parties. At December 31, 2017, the Company had obligations to related parties for $0.1 million recorded in other accrued expenses and current liabilities. At December 31, 2017, the Company had receivables from an entity for which the Company had an equity investment, FluiDyna, for $0.5 million recorded in other long-term assets. The Company acquired FluiDyna in May 2018; as a result, the receivable has been eliminated from the December 31, 2018 consolidated balance sheet. For additional information on the acquisition of FluiDyna, see Note 4 - Acquisitions.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2018
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	19. Commitments and contingencies Swedish Tax Litigation The Swedish Tax Authorities, or STA, have assessed tax, penalties and interest in the amount of $6.7 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 removed 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 and is now contesting the STA position in the first level of administrative courts. MSC Litigation In July 2007, MSC Software Corporation filed a lawsuit against the Company alleging misappropriation of trade secrets, breach of confidentiality and other claims. On April 10, 2014, a jury returned a verdict against the Company. The Company challenged the verdict and on November 13, 2014, a judge vacated all but $0.4 million of the judgment and ordered a new trial on damages. On December 13, 2017, the court granted Altair’s motion for summary judgment and dismissed MSC’s claim of trade secret misappropriation. 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 $9.7 million, $9.3 million, and $7.9 million for the years ended December 31, 2018, 2017 and 2016, respectively, and are reported in Cost of revenue—software and Cost of revenue—other. Leases The Company leases office space, vehicles, and computer equipment. Such leases, some of which are noncancelable, are set to expire at various dates. Certain of these lease arrangements contain escalation clauses whereby monthly rent increases over time. The future minimum annual lease payments under noncancelable operating leases with an initial term in excess of one year and future minimum capital lease payments at December 31, 2018, are as follows (in thousands): Capital leases Operating leases Year Ending December 31, 2019 $ 256 $ 10,661 2020 209 8,306 2021 173 5,673 2022 137 3,573 2023 38 1,819 Thereafter — 3,147 Total minimum lease payments 813 $ 33,179 Less: current installments under capital lease obligations 256 Total long-term portion $ 557 Rent expense for operating leases was $11.0 million, $9.9 million and $8.5 million for the years ended December 31, 2018, 2017 and 2016, respectively.

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2018
Segment Reporting [Abstract]
Segment Information	20. 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. 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 ® ® 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, 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, 2016 Software CES All other Total Revenue $ 259,588 $ 47,702 $ 5,950 $ 313,240 Adjusted EBITDA $ 29,411 $ 5,425 $ (4,006 ) $ 30,830 Year ended December 31, 2018 2017 2016 Reconciliation of Adjusted EBITDA to GAAP income (loss) before income taxes: Adjusted EBITDA $ 50,180 $ 22,517 $ 30,830 Stock-based compensation expense (3,339 ) (47,281 ) (5,132 ) Interest expense (200 ) (2,160 ) (2,265 ) Interest income and other (1) (4,883 ) 2,260 249 Depreciation and amortization (14,734 ) (11,747 ) (9,980 ) Income (loss) before income taxes $ 27,024 $ (36,411 ) $ 13,702 (1) 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, c) impairment charges for royalty contracts and trade names resulting in $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 resulting in $2.0 million of income in each year. 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, 2018 2017 2016 2018 2017 United States $ 186,026 $ 142,679 $ 139,079 $ 63,266 $ 38,729 Other countries 8,604 6,404 6,032 11,447 116 Total Americas 194,630 149,083 145,111 74,713 38,845 Germany 45,664 43,751 39,470 4,305 2,802 France 16,154 18,128 15,729 1,583 2,176 Other countries 42,846 40,050 34,909 4,729 4,534 Total Europe, Middle East and Africa 104,664 101,929 90,108 10,617 9,512 Japan 35,478 33,686 33,198 2,045 2,237 Other countries 61,607 48,635 44,823 2,957 2,574 Total Asia Pacific 97,085 82,321 78,021 5,002 4,811 Total $ 396,379 $ 333,333 $ 313,240 $ 90,332 $ 53,168 (1) Includes property and equipment, net and definite-lived intangible assets, net.

Supplemental quarterly financia

Supplemental quarterly financial information (unaudited)	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Supplemental Quarterly Financial Information (Unaudited)	21. Supplemental quarterly financial information (unaudited) 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 ASC 606 (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 $ 84,216 $ 63,903 $ 59,547 $ 72,740 Operating income (loss) $ 26,146 $ 175 $ 1,880 $ (3,557 ) Net income (loss) $ 24,684 $ (1,080 ) $ 934 $ (10,823 ) Net income (loss) per share, basic $ 0.39 $ (0.02 ) $ 0.01 $ (0.15 ) Net income (loss) per share, diluted $ 0.34 $ (0.02 ) $ 0.01 $ (0.15 ) Revenue for the first and fourth quarters of 2018 are higher than the second and third quarters of 2018 as a result of the adoption of ASC 606. The Company typically has higher billings in the first and fourth quarters of each year, and the guidance under ASC 606 accelerates revenue. Gross profit, operating income, and net income are significantly higher in the first quarter of 2018, than the second, third and fourth quarters of 2018 due to the adoption 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 net loss in the fourth quarter of 2018 is primarily the result of transaction costs from the acquisition of Datawatch. See Note 4 – Acquisitions. Three months ended ASC 605 (in thousands) March 31, 2018 June 30, 2018 September 30, 2018 December 31, 2018 Total revenue $ 91,731 $ 95,566 $ 93,871 $ 103,894 Gross profit $ 62,689 $ 66,110 $ 66,667 $ 73,623 Operating income (loss) $ 4,270 $ 2,177 $ 8,968 $ (2,424 ) Operating income in the first quarter of 2018 includes a non-recurring adjustment for a change in estimated legal expenses resulting in $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. Three months ended (1) (in thousands, except per share data) March 31, 2017 June 30, 2017 September 30, 2017 December 31, 2017 Total revenue $ 76,882 $ 81,646 $ 84,938 $ 89,867 Gross profit $ 50,128 $ 54,728 $ 58,636 $ 63,250 Operating loss $ (1,990 ) $ (7,158 ) $ (20,928 ) $ (3,181 ) Net loss $ (2,188 ) $ (7,246 ) $ (29,626 ) $ (60,347 ) Net loss per share, basic $ (0.04 ) $ (0.14 ) $ (0.59 ) $ (1.03 ) Net loss per share, diluted $ (0.04 ) $ (0.14 ) $ (0.59 ) $ (1.03 ) ____________________________________________________________________ (1) The three months ended March 31, 2017, June 30, 2017, September 30, 2017 and December 31, 2017 have been reported under ASC 605 and have not been adjusted under the modified retrospective approach. See Note 3 – Revenue from contracts with customers for the effect of the adoption of ASC 606 on the Company’s consolidated financial statements. In the second, third and fourth quarters of 2017, the Company recognized stock-based compensation expense of $11.2 million, $25.3 million, and $8.0 million, respectively. Income tax expense increased by $56.6 million for the quarter ended December 31, 2017. This increase is primarily due to a $47.0 million increase in tax expense related to the recording of a valuation allowance on the U.S. deferred tax assets, and a $15.4 million increase due to the remeasurement of net deferred tax assets and liabilities as part of the Tax Act offset by other tax accounting benefits in the U.S. in the quarter.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
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	Reclassifications Certain prior period amounts included in the 2017 and 2016 consolidated statements of cash flows have been reclassified to conform to the current year presentation. Specifically, in the accompanying consolidated statement of cash flows for the years ended December 31, 2017 and 2016, Gain on sale of assets held for sale and other has been reclassified out of Other operating activities. This reclassification had no effect on Net cash provided by operating activities. Additionally, Proceeds from the sale of assets held for sale and other has been reclassified out of Other investing activities. This reclassification had no effect on Net cash used in investing activities.
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 determination of the period of benefit for capitalized costs to obtain a contract, 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	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, Cost of Revenue, and Deferred 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 recent 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. 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 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. Deferred revenue Deferred revenue consists of customer billings or payments received in advance of the recognition of revenue and is recognized as revenue when revenue recognition criteria are met.
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, 2018 2017 Cash and cash equivalents $ 35,345 $ 39,213 Restricted cash included in other long-term assets 340 365 Total cash, cash equivalents, and restricted cash shown in the statement of cash flows $ 35,685 $ 39,578 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, 2018 2017 Accounts receivable, trade $ 93,073 $ 82,185 Contract assets 3,730 4,450 Accounts receivable, net $ 96,803 $ 86,635 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 $1.2 million and $0.8 million at December 31, 2018 and 2017, respectively. Activity in the allowance for doubtful accounts was as follows (in thousands): For the year ended December 31, 2018 2017 2016 Balance, beginning of year $ (798 ) $ (565 ) $ (937 ) Provision charged to expense (394 ) (610 ) (291 ) Write-offs, net of recoveries 3 414 638 Effects of foreign currency translation 39 (37 ) 25 Balance, end of year $ (1,150 ) $ (798 ) $ (565 )
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 45%, 50%, and 50% of the Company’s 2018, 2017 and 2016 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, 2018, 2017 or 2016.
Inventory	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.
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 2018, 2017, or 2016.
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, 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 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 it is determined that the estimated fair value of the reporting unit is more likely than not less than its carrying amount, including goodwill, the two-step goodwill impairment test is required. Otherwise, no further analysis would be required. For 2017 and 2016, 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 may skip the qualitative assessment, or if the two-step impairment test for goodwill is deemed necessary, this quantitative impairment analysis compares the fair value of the Company’s reporting unit to its related carrying value. If the fair value of the reporting unit exceeds its carrying amount, step two does not need to be performed. If the fair value of the reporting unit is less than its carrying amount, an indication of goodwill impairment exists and the Company must perform step two of the impairment test. Under step two, an impairment loss is recognized for any excess of the carrying amount of the reporting unit’s goodwill over the implied fair value of that goodwill. The implied fair value of goodwill is determined by allocating the fair value of the reporting unit in a manner similar to a purchase price allocation and the residual fair value after this allocation is the implied fair value of the reporting unit goodwill. Fair value of the reporting units is determined using an income approach. The income approach is based on projected debt-free cash flows which are discounted to the present value using discount factors that consider the timing and risk of cash flows. The Company also takes into consideration a multiple of earnings valuation technique. The Company believes that this approach is appropriate because it provides a reasonable estimate of the price that would be received to sell the reporting unit in an orderly transaction between market participants at the measurement date. While there are inherent uncertainties related to the assumptions used in this analysis, the Company believes that this approach provides a reasonable estimate of fair value. 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. During the quarter ended September 30, 2018, the Company performed an interim 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. Three was no indication of impairment of other indefinite-lived intangible assets for the Company’s annual test which is completed in the fourth quarter. No impairment charges were recognized in 2017 and 2016.
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, 2018, the Company had approximately $11.7 million receivable from the French government related to CIR, of which $2.6 million is recorded in income tax receivable and the remaining $9.1 million is recorded in other long-term assets. As of December 31, 2017, the Company had approximately $10.2 million receivable from the French government related to CIR, of which $3.3 million was recorded in income tax receivable and the remaining $6.9 million was recorded in other long-term assets. CIR is subject to customary audit by the French tax authorities.
Valuation of Common Stock Prior to IPO	Valuation of common stock prior to IPO Due to the absence of an active market for the Company’s common stock prior to the Company’s IPO in the fourth quarter of 2017, the Board of Directors, with the assistance of a third-party valuation specialist, determined the fair value of the Company’s common stock. The valuation methodology included estimates and assumptions including forecasts of future cash flows that required significant judgments. These valuations considered a number of objective and subjective factors, including the Company’s actual operating and financial performance, external market conditions, performance of comparable publicly traded companies, comparable transactions, business developments, likelihood of achieving a liquidity event, such as an initial public offering or sale, and common stock transactions, among other factors. The Company utilized methodologies in accordance with the framework of the American Institute of Certified Public Accountants’ Technical Practice Aid, Valuation of Privately-Held Company Equity Securities issued as Compensation,
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 $97.6 million, $93.2 million, and $71.3 million for the years ended December 31, 2018, 2017 and 2016, respectively.
Advertising Costs	Advertising costs Advertising costs are expensed as incurred. Advertising expenses were $4.4 million, $3.5 million and $2.5 million for the years ended December 31, 2018, 2017, and 2016, 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, 2018, the classification remains as mezzanine equity.
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 the quarter ended June 30, 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 in the fourth quarter of 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.
Recent Accounting Guidance	Recent accounting guidance Accounting standards adopted The Company ceased to qualify as an emerging growth company (as defined in the Jumpstart Our Business Startups Act of 2012) as of December 31, 2018, therefore all of the 2018 public company adoptions are reflected in this Annual Report on Form 10-K. Revenue Recognition —In May 2014, the Financial Accounting Standards Board, or “FASB”, issued ASU No. 2014-09, (ASU 2014-09). The Company adopted ASU 2014-09 and its related amendments, or ASC 606, effective January 1, 2018 using the modified retrospective approach for all contracts not completed as of the date of adoption. Results as of and for the year ended December 31, 2018 are presented under ASC 606, while prior period amounts are not adjusted and continue to be reported in accordance with ASC 605, Revenue Recognition (ASC 605) and other industry specific guidance. Under ASC 605, the Company did not report “License” and “Maintenance and other services” revenue or cost of revenue. Therefore, the Company could not report these amounts for comparable prior periods. See Note 3 – Revenue from contracts with customers for the effect of the adoption of ASC 606 on the Company’s consolidated financial statements. Financial Instruments —In January 2016, the FASB issued Accounting Standards Update (“ASU”) No. 2016-01, . The Company adopted this standard effective January 1, 2018. This standard affects the accounting for equity instruments, financial liabilities under the fair value option and the presentation and disclosure requirements of financial instruments. The adoption did not have a material effect on the Company’s consolidated financial statements. Cash Classification —In August 2016, the FASB issued ASU No. 2016-15, , The Company adopted ASU 2016-15 effective January 1, 2018, on a retrospective basis. This standard provides guidance for targeted changes with respect to how cash receipts and cash payments are classified in the statements of cash flows. The adoption did not have a material effect on the Company’s consolidated financial statements. Retirement Benefits – In March 2017, the FASB issued ASU 2017-07, The Company adopted ASU 2017-07 effective January 1, 2018. This ASU provides guidance on the presentation of the service cost component and the other components of net period pension cost in the consolidated statements of operations. The adoption did not have a material effect on the Company’s consolidated financial statements. Stock Compensation – In May 2017, the FASB issued ASU 2017-09, which amends the guidance about which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting in Topic 718. This change is required to be applied prospectively to an award modified on or after the adoption date. The Company adopted this standard on January 1, 2018, and will apply this guidance to modifications of stock-based compensation arrangements after this date. The adoption did not have a material effect on the Company’s consolidated financial statements. Accounting standards not yet adopted Leases —In February 2016, the FASB issued ASU No. 2016-02, . This standard amends various aspects of existing accounting guidance for leases, including the recognition of a right-of-use asset and a lease liability on the balance sheet for all leases with terms longer than 12 months. Leases will be classified as either finance or operating, with classification affecting the pattern of expense recognition in the income statement. This standard also introduces new disclosure requirements for leasing arrangements. The Company is adopting ASU 2016-02 on January 1, 2019 and plans to elect the optional transition method as well as the package of practical expedients upon adoption. The Company is currently in the process of completing its review of lease contracts, evaluating other contracts for potential embedded leases, and establishing new processes and revised internal controls. Upon adoption, the Company expects to record a right of use asset and a corresponding lease liability for its operating leases where the Company is the lessee. The potential impact on the Company’s consolidated financial statements is largely based on the present value of future minimum lease payments, the amount of which will depend upon the population of leases in effect at the date of adoption. Future minimum lease payments totaled $33.2 million as of December 31, 2018, as disclosed in Note 19 - Commitments and contingencies. Goodwill Impairment —In January 2017, the FASB issued ASU No. 2017-04, , 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 new standard must be applied on a prospective basis. The adoption of this guidance is not expected to have a material impact on the Company’s consolidated financial statements. Derivatives and Hedging – In August 2017, the FASB issued ASU 2017-12, 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 amendments are effective for annual and interim reporting periods beginning after December 15, 2018, with early adoption permitted. The adoption of this guidance is not expected to have a material impact on the Company’s consolidated financial statements. Comprehensive Income – In February 2018, the FASB issued ASU 2018-02, , 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 new guidance may be applied retrospectively to each period in which the effect of the Tax Act is recognized in the period of adoption. The Company must adopt this guidance for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. Early adoption is permitted for periods for which financial statements have not yet been issued or made available for issuance, including the period the Tax Act was enacted. The guidance, when adopted, will require new disclosures regarding a company’s accounting policy for releasing the tax effects in AOCI and permit the company the option to reclassify to retained earnings the tax effects resulting from the Tax Act that are stranded in AOCI. The Company is currently evaluating how to apply the new guidance and has not determined whether it will elect to reclassify stranded amounts. The adoption of ASU 2018-02 is not expected to have a material effect on the Company’s consolidated financial statements and related disclosures. Stock Compensation – In June 2018, the FASB issued ASU 2018-07, 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. Under the guidance, the measurement of equity-classified nonemployee awards will be fixed at the grant date, which may lower an entity’s cost and reduce volatility in the income statement. The amendments are effective for fiscal years beginning after December 15, 2018, including interim periods within that fiscal year. Early adoption is permitted, including in an interim period, but not before an entity adopts ASC 606, The adoption of this guidance is not expected to have a material effect on the Company’s 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. 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. T he amendments are effective for fiscal years ending after December 15, 2020, early adoption is permitted. The adoption of this guidance is not expected to have a material impact on the Company’s 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.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
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, 2018 2017 Cash and cash equivalents $ 35,345 $ 39,213 Restricted cash included in other long-term assets 340 365 Total cash, cash equivalents, and restricted cash shown in the statement of cash flows $ 35,685 $ 39,578
Schedule of Accounts Receivable Net	Accounts receivable, net consisted of the following (in thousands): December 31, 2018 2017 Accounts receivable, trade $ 93,073 $ 82,185 Contract assets 3,730 4,450 Accounts receivable, net $ 96,803 $ 86,635
Schedule of Allowance for Doubtful Accounts	Activity in the allowance for doubtful accounts was as follows (in thousands): For the year ended December 31, 2018 2017 2016 Balance, beginning of year $ (798 ) $ (565 ) $ (937 ) Provision charged to expense (394 ) (610 ) (291 ) Write-offs, net of recoveries 3 414 638 Effects of foreign currency translation 39 (37 ) 25 Balance, end of year $ (1,150 ) $ (798 ) $ (565 )

Revenue from Contracts with C_2

Revenue from Contracts with Customers (Tables)	12 Months Ended
	Dec. 31, 2018
Disaggregation Of Revenue [Line Items]
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, 2018 (ASC 606) 2017 (ASC 605) (1) 2016 (ASC 605) (1) Software revenue: Term licenses $ 168,909 Perpetual licenses 38,255 Maintenance 86,150 Professional services and other 11,047 Total software revenue $ 304,361 $ 244,817 $ 223,818
ASC 606 [Member]
Disaggregation Of Revenue [Line Items]
Schedule of Cumulative Impact of Adoption of ASC 606 in Financial Statements	The following table summarizes the cumulative impact of adoption of the new revenue standard for revenue recognition on line items within the consolidated balance sheets (in thousands): As of December 31, 2017 Prior to adoption of ASC 606 Adjustments for ASC 606 As Adjusted Prepaid expenses and other current assets $ 10,006 $ 1,589 $ 11,595 Deferred tax assets $ 8,351 $ (12,352 ) $ (4,001 ) Other long-term assets $ 17,019 $ 128 $ 17,147 Other accrued expenses and current liabilities $ 21,744 $ 1,049 $ 22,793 Deferred revenue, current $ 130,122 $ (77,645 ) $ 52,477 Deferred revenue, non-current $ 9,640 $ (5,263 ) $ 4,377 Other long-term liabilities $ 17,647 $ 445 $ 18,092 Accumulated deficit $ (166,499 ) $ 70,779 $ (95,720 ) As of December 31, 2018 Prior to adoption of ASC 606 Adjustments for ASC 606 As Reported Prepaid expenses and other current assets $ 13,693 $ 1,798 $ 15,491 Deferred tax assets $ 14,092 $ (12,719 ) $ 1,373 Other long-term assets $ 17,077 $ 211 $ 17,288 Other accrued expenses and current liabilities $ 25,435 $ 912 $ 26,347 Deferred revenue, current $ 144,710 $ (84,945 ) $ 59,765 Deferred revenue, non-current $ 13,791 $ (7,037 ) $ 6,754 Other long-term liabilities $ 27,636 $ 517 $ 28,153 Accumulated deficit $ (163,600 ) $ 81,595 $ (82,005 ) Accumulated other comprehensive loss $ (9,300 ) $ (1,752 ) $ (11,052 ) 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 $ 12,472 $ 837 $ 13,309 Net income $ 2,899 $ 10,816 $ 13,715 Income per share: Basic $ 0.04 $ 0.16 $ 0.20 Diluted $ 0.04 $ 0.14 $ 0.18

Acquisitions (Tables)

Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2018
Datawatch Corporation [Member]
Summary of Amounts of Identified Assets Acquired and Liabilities Assumed at the Acquisition Date	The following table summarizes the preliminary 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 10,784 Other assets 3,055 Property and equipment 980 Trade names 7,400 Developed technology (6-year life) 22,600 Customer relationships (10-year life) 16,400 Accounts payable and other liabilities (5,393 ) Deferred revenue (4,100 ) Other long-term liabilities (7,928 ) Total net identifiable assets acquired and liabilities assumed 52,076 Goodwill (1) $ 131,351
Schedule of Pro Forma Financial Information	The unaudited pro forma financial information was as follows (in thousands, except per share data): Year ended December 31, 2018 2017 Total revenue $ 435,414 $ 363,906 Net income (loss) $ 7,613 $ (115,010 ) Net income (loss) per share attributable to common stockholders, basic $ 0.11 $ (2.19 ) Net income (loss) per share attributable to common stockholders, diluted $ 0.10 $ (2.19 )
SIMSOLID Corporation [Member]
Summary of Amounts of Identified Assets Acquired and Liabilities Assumed at the Acquisition Date	The following table summarizes the consideration transferred to acquire SIMSOLID and the amounts of identified assets acquired and liabilities assumed at the acquisition date (in thousands): Fair value of consideration transferred $ 22,139 Recognized amounts of identifiable assets acquired and liabilities assumed: Current assets $ 135 Trade names 344 Developed technology 3,291 Current liabilities (141 ) Long term liabilities (960 ) Total net identifiable assets acquired and liabilities assumed 2,669 Goodwill $ 19,470
Runtime [Member]
Summary of Amounts of Identified Assets Acquired and Liabilities Assumed at the Acquisition Date	The following table summarizes the consideration transferred to acquire Runtime and the amounts of identified assets acquired and liabilities assumed at the acquisition date (in thousands): Fair value of consideration transferred $ 25,508 Recognized amounts of identifiable assets acquired and liabilities assumed: Cash 564 Accounts receivable 2,257 Deferred tax assets 1,713 Other assets 257 Trade names 440 Developed technology (4-year life) 7,870 Customer relationships (7-year life) 2,490 Accounts payable and other liabilities (1,000 ) Deferred revenue (1,925 ) Deferred tax liabilities (4,645 ) Total net identifiable assets acquired and liabilities assumed 8,021 Goodwill $ 17,487
Carriots [Member]
Summary of Amounts of Identified Assets Acquired and Liabilities Assumed at the Acquisition Date	The following table summarizes the consideration transferred to acquire Carriots and the amounts of identified assets acquired and liabilities assumed at the acquisition date (in thousands): Fair value of consideration transferred $ 6,657 Recognized amounts of identifiable assets acquired and liabilities assumed: Deferred tax assets 394 Other assets 472 Trade names 252 Developed technology (4-year life) 1,317 Customer relationships (7-year life) 296 Accounts payable and other liabilities (1,015 ) Total net identifiable assets acquired and liabilities assumed 1,716 Goodwill $ 4,941

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	12 Months Ended
	Dec. 31, 2018
Property Plant And Equipment [Abstract]
Summary of Property and Equipment	Property and equipment consisted of the following (in thousands): Estimated December 31, useful lives 2018 2017 Land Indefinite $ 7,994 $ 7,994 Building and improvements 5-39 years 13,120 15,185 Computer equipment and software 3-5 years 34,582 32,103 Office furniture and equipment 5-15 years 7,958 6,751 Leasehold improvements (1 ) 6,926 6,467 Total property and equipment 70,580 (2) 68,500 (2) Less: accumulated depreciation and amortization 40,427 37,054 Property and equipment, net $ 30,153 $ 31,446 (1) Shorter of lease term or estimated useful life, generally ranging from five to ten years. (2) Equipment under capital lease obligations had an original carrying value of approximately $2.0 million and $1.1 million at December 31, 2018 and 2017, respectively.

Goodwill and Other Intangible_2

Goodwill and Other Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
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, 2016 $ 36,625 Acquisitions 22,420 Effects of foreign currency translation 3,661 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
Schedule of Other Intangible Assets	A summary of other intangible assets is shown below (in thousands): 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 December 31, 2017 Weighted average amortization period Gross carrying amount Accumulated amortization Net carrying amount Definite-lived intangible assets: Developed technology 4 years $ 25,947 $ 9,909 $ 16,038 Customer relationships 7 years 11,794 6,195 5,599 Other intangibles 10 years 143 57 86 Total definite-lived intangible assets 37,884 16,161 21,723 Indefinite-lived intangible assets: Trade names 2,738 2,738 Total other intangible assets $ 40,622 $ 16,161 $ 24,461
Summary of Estimated Amortization Expense	Estimated amortization expense for the next five years as of December 31, 2018 is as follows (in thousands): Year ending December 31, 2019 $ 13,880 December 31, 2020 $ 12,959 December 31, 2021 $ 10,590 December 31, 2022 $ 7,378 December 31, 2023 $ 6,627

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Schedule of Carrying Value of Debt	The carrying value of debt is as follows (in thousands): December 31, 2018 2017 Revolving credit facility $ 30,950 $ — Obligations held under capital leases (Note 19) 813 207 Other borrowings 75 203 Total debt 31,838 410 Less: unamortized debt issuance costs 90 — Less: current portion of long-term debt 331 232 Long-term debt, net of current portion $ 31,417 $ 178
Scheduled Maturities of Long Term Debt	At December 31, 2018, future maturities of long-term debt, excluding capital leases, were as follows (in thousands): Year ending December 31, 2019 $ 75 2020 — 2021 — 2022 30,950 2023 — Total $ 31,025

Other Liabilities (Tables)

Other Liabilities (Tables)	12 Months Ended
	Dec. 31, 2018
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, 2018 2017 Accrued VAT $ 4,536 $ 3,916 Income taxes payable 4,458 3,724 Accrued professional fees 3,165 2,500 Accrued royalties 2,613 2,037 Billings in excess of cost 1,504 832 Defined contribution plan liabilities 1,376 1,274 Government grants 915 712 Non-income tax liabilities 853 1,343 Related party liabilities — 119 Other current liabilities 6,927 5,287 Total $ 26,347 $ 21,744
Summary of Other Long-term Liabilities	The following table provides the details of other long-term liabilities (in thousands): December 31, 2018 2017 Pension and other post retirement liabilities $ 9,111 $ 7,670 Deferred tax liabilities 7,736 1,620 Other liabilities 11,306 8,357 Total $ 28,153 $ 17,647

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Summary of Changes in the Fair Value of Company's Level 3 Financial Liabilities	The following table sets forth a summary of the changes in the fair value of the Company’s Level 3 financial liabilities (in thousands): Liability for Class A redeemable common shares Liability for stock-based compensation awards Balance at December 31, 2016 $ 10,632 $ 11,604 Exercise of stock options 432 (411 ) Forfeitures of stock options — (157 ) Change in fair value 19,223 25,191 Modification to stock options as a result of the Company’s IPO (1) (30,287 ) (36,227 ) Balance at December 31, 2017 $ — $ — (1) As a result of the Company’s IPO in the fourth quarter of 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 in the fourth quarter of 2017 in accordance with ASC 718.

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2018
Summary of Stock Option Activity	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, 2018 888,864 $ 0.67 2.5 $ 20.7 Exercised (356,644 ) $ 0.69 Forfeited — $ — Outstanding and exercisable at December 31, 2018 532,220 $ 0.65 1.4 $ 14.3
Summary of Restricted Stock Units Awarded	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, 2018 — Granted 228,201 Vested (1,000 ) Forfeited (21,140 ) Outstanding at December 31, 2018 206,061
Weighted Average Assumptions to Calculate Fair Value of Options Granted	The weighted average assumptions used in the Black-Scholes option pricing model used to calculate the fair value of options granted during the years ended December 31, 2017 and 2016 are as follows: 2017 grants 2016 grants Weighted average grant date fair value per share $1.86 - $1.94 $1.42 - $1.65 Expected volatility 34 % 37 % Expected term (in years) 5.75-6.25 5.75-6.25 Risk-free interest rate 2.02 % 1.37%-1.79% 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, 2018 2017 2016 Cost of revenue-software $ 31 $ 350 $ 22 Research and development 740 12,540 1,370 Sales and marketing 910 7,693 775 General and administrative 1,658 26,698 2,965 Total stock-based compensation expense $ 3,339 $ 47,281 $ 5,132
NSO Plan [Member]
Summary of Stock Option Activity	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, 2018 6,441,972 $ 0.000025 19.0 $ 154.1 Exercised (2,104,116 ) $ 0.000025 Forfeited — $ — Outstanding and exercisable at December 31, 2018 4,337,856 $ 0.000025 18.0 $ 119.6
2012 Plan [Member]
Summary of Stock Option Activity	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, 2018 2,183,127 $ 3.74 7.3 $ 44.1 Granted — $ — Exercised (623,119 ) $ 2.76 Forfeited (18,843 ) $ 4.68 Outstanding at December 31, 2018 1,541,165 $ 4.12 6.9 $ 36.2 Exercisable at December 31, 2018 975,291 $ 3.70 6.1 $ 23.3

Other (Income) Expense, Net (Ta

Other (Income) Expense, Net (Tables)	12 Months Ended
	Dec. 31, 2018
Other Income And Expenses [Abstract]
Schedule of Other (Income) Expense, Net	Other (income) expense, net consists of the following (in thousands): Year ended December 31, 2018 2017 2016 Foreign exchange (gain) loss $ (626 ) $ 1,254 $ (271 ) Other (1,954 ) (260 ) (249 ) Other (income) expense, net $ (2,580 ) $ 994 $ (520 )

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Components of Income (Loss) Before Income Taxes	The components of income (loss) before income taxes are as follows (in thousands): Year ended December 31, 2018 2017 2016 U.S. $ 4,228 $ (49,761 ) $ (2,225 ) Non-U.S. 22,796 13,350 15,927 $ 27,024 $ (36,411 ) $ 13,702
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, 2018 2017 2016 Current U.S. Federal $ 2 $ — $ — Non-U.S. 12,552 10,290 9,413 U.S. State and Local (8 ) 135 202 Total current 12,546 10,425 9,615 Deferred U.S. Federal 1,714 54,130 (5,358 ) Non-U.S. (934 ) (1,306 ) (610 ) U.S. State and Local (17 ) (253 ) (108 ) Total deferred 763 52,571 (6,076 ) Income tax expense $ 13,309 $ 62,996 $ 3,539
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, 2018 2017 2016 U.S. federal statutory rate 21 % 35 % 35 % Income taxes at U.S. federal statutory rate $ 5,675 $ (12,744 ) $ 4,796 Foreign income taxes at rates other than the federal statutory rate 2,096 373 (584 ) U.S. state and local income taxes, net of U.S. federal tax benefit (3,446 ) (155 ) 94 U.S. Tax Cut and Jobs Act: transition tax, net of foreign tax credits — 4,187 — Global intangible low-taxed income 6,587 — — Change in valuation allowance 16,725 47,429 — Foreign withholding taxes 5,103 4,181 4,235 Foreign dividends — — 5,077 U.S. foreign tax credit (4,564 ) (4,154 ) (8,786 ) Research and development tax credit (2,819 ) (2,999 ) (2,696 ) Domestic production activities deduction — — (840 ) Non-deductible stock-based compensation (14,964 ) 10,871 2,064 Meals & entertainment 181 358 235 Other 672 (163 ) (91 ) Deferred tax on investment in subsidiary — — (264 ) Uncertain tax positions 903 446 299 Acquisition costs 503 — — Tax law changes 657 15,366 — Income tax expense $ 13,309 $ 62,996 $ 3,539
Schedule of Deferred Tax Assets and Liabilities	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, 2018 2017 Deferred tax assets: Deferred revenue $ 3,063 $ 19,569 Net operating loss carryforwards 37,549 7,601 Tax credit carryforwards 30,516 22,191 Stock-based compensation 6,858 8,922 Capitalized research and development 8,266 8,798 Accrued expenses — 648 Employee benefits 4,825 3,931 Other 1,777 1,905 Total gross deferred tax assets 92,854 73,565 Less: valuation allowances (76,101 ) (54,331 ) Net deferred tax assets (1) 16,753 19,234 Deferred tax liabilities: Prepaid royalties 7,687 6,925 Property and equipment and intangibles 13,945 4,567 Deferred tax on investment in subsidiary 329 272 Other 1,155 739 Total deferred tax liabilities 23,116 12,503 Total net deferred tax assets $ (6,363 ) $ 6,731 (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, 2018, 2017 and 2016 (in thousands): December 31, 2018 2017 2016 Beginning balance $ 54,331 $ 4,153 $ 2,452 Additions charged to expense 16,725 47,429 177 Deductions — — (207 ) Other 5,045 2,749 1,731 Ending balance $ 76,101 $ 54,331 $ 4,153
Summary of Tax Credit Carryforwards	The following table summarizes the amount and expiration dates of operating loss and tax credit carryforwards at December 31, 2018 (in thousands): Expiration dates Amounts U.S. general business credits and loss carryforwards 2019-Indefinite $ 53,853 Foreign loss carryforwards Indefinite 8,030 U.S. foreign tax credits 2028 6,182 Total operating loss and tax credit carryforwards $ 68,065
Summary of Operating Loss Carryforwards	The following table summarizes the amount and expiration dates of operating loss and tax credit carryforwards at December 31, 2018 (in thousands): Expiration dates Amounts U.S. general business credits and loss carryforwards 2019-Indefinite $ 53,853 Foreign loss carryforwards Indefinite 8,030 U.S. foreign tax credits 2028 6,182 Total operating loss and tax credit carryforwards $ 68,065
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, 2018 2017 2016 Unrecognized tax benefits—January 1 $ 6,157 $ 5,604 $ 5,305 Increase in unrecognized tax benefits as a result of: Additions for tax positions of current period 234 634 299 Additions for tax positions of prior periods 10,866 — — Reductions for tax positions of prior periods (100 ) (81 ) — Reductions due to statute of limitations (60 ) — — Unrecognized tax benefits—December 31 $ 17,097 $ 6,157 $ 5,604

Income (Loss) Per Share (Tables

Income (Loss) Per Share (Tables)	12 Months Ended
	Dec. 31, 2018
Earnings Per Share [Abstract]
Computation of Numerators and Denominators Used 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 income (loss) per share amounts (in thousands, except per share data): Year ended December 31, 2018 2017 2016 Numerator: Net income (loss) $ 13,715 $ (99,407 ) $ 10,163 Denominator: Denominator for basic income (loss) per share— weighted average shares 67,468 52,466 48,852 Effect of dilutive securities, stock options and RSUs 7,410 — 9,004 Denominator for dilutive income (loss) per share 74,878 52,466 57,856 Net income (loss) per share attributable to common stockholders, basic $ 0.20 $ (1.89 ) $ 0.21 Net income (loss) per share attributable to common stockholders, diluted $ 0.18 $ (1.89 ) $ 0.18

Retirement Benefits (Tables)

Retirement Benefits (Tables)	12 Months Ended
	Dec. 31, 2018
Compensation And Retirement Disclosure [Abstract]
Schedule of Pension Benefits Obligation Recorded in Consolidated Balance Sheets	A summary of the components of the pension benefits obligation recorded in the consolidated balance sheets are as follows (in thousands): December 31, 2018 2017 Accrued compensation and benefits $ 513 $ 368 Other long-term liabilities 9,111 7,670 $ 9,624 $ 8,038
Schedule of Estimated Future Benefit Payments	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, 2019 $ 537 December 31, 2020 $ 356 December 31, 2021 $ 283 December 31, 2022 $ 337 December 31, 2023 $ 519 Next five years $ 2,484

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Loss (Tables)	12 Months Ended
	Dec. 31, 2018
Equity [Abstract]
Components of 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, 2015 $ (5,745 ) $ (963 ) $ (6,708 ) Other comprehensive income (loss) before reclassification 80 (771 ) (691 ) Tax effects (60 ) 195 135 Other comprehensive income (loss) 20 (576 ) (556 ) 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 (5,211 ) 90 (5,121 ) Amounts reclassified from accumulated other comprehensive loss — (1,177 ) (1,177 ) Tax effects — 318 318 Other comprehensive income (loss) (5,211 ) (769 ) (5,980 ) Balance at December 31, 2018 $ (8,585 ) $ (2,467 ) $ (11,052 )

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2018
Commitments And Contingencies Disclosure [Abstract]
Schedule of Future Minimum Annual Lease Payments under Noncancelable Operating Leases and Capital Leases	The future minimum annual lease payments under noncancelable operating leases with an initial term in excess of one year and future minimum capital lease payments at December 31, 2018, are as follows (in thousands): Capital leases Operating leases Year Ending December 31, 2019 $ 256 $ 10,661 2020 209 8,306 2021 173 5,673 2022 137 3,573 2023 38 1,819 Thereafter — 3,147 Total minimum lease payments 813 $ 33,179 Less: current installments under capital lease obligations 256 Total long-term portion $ 557

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2018
Segment Reporting [Abstract]
Schedule of Segment Reporting Information	The following tables are in thousands: 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, 2016 Software CES All other Total Revenue $ 259,588 $ 47,702 $ 5,950 $ 313,240 Adjusted EBITDA $ 29,411 $ 5,425 $ (4,006 ) $ 30,830
Reconciliation of U.S. GAAP (Loss) Income Before Income Taxes to Adjusted EBITDA	Year ended December 31, 2018 2017 2016 Reconciliation of Adjusted EBITDA to GAAP income (loss) before income taxes: Adjusted EBITDA $ 50,180 $ 22,517 $ 30,830 Stock-based compensation expense (3,339 ) (47,281 ) (5,132 ) Interest expense (200 ) (2,160 ) (2,265 ) Interest income and other (1) (4,883 ) 2,260 249 Depreciation and amortization (14,734 ) (11,747 ) (9,980 ) Income (loss) before income taxes $ 27,024 $ (36,411 ) $ 13,702 (1) 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, c) impairment charges for royalty contracts and trade names resulting in $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 resulting in $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, 2018 2017 2016 2018 2017 United States $ 186,026 $ 142,679 $ 139,079 $ 63,266 $ 38,729 Other countries 8,604 6,404 6,032 11,447 116 Total Americas 194,630 149,083 145,111 74,713 38,845 Germany 45,664 43,751 39,470 4,305 2,802 France 16,154 18,128 15,729 1,583 2,176 Other countries 42,846 40,050 34,909 4,729 4,534 Total Europe, Middle East and Africa 104,664 101,929 90,108 10,617 9,512 Japan 35,478 33,686 33,198 2,045 2,237 Other countries 61,607 48,635 44,823 2,957 2,574 Total Asia Pacific 97,085 82,321 78,021 5,002 4,811 Total $ 396,379 $ 333,333 $ 313,240 $ 90,332 $ 53,168 (1) Includes property and equipment, net and definite-lived intangible assets, net.

Supplemental Quarterly Financ_2

Supplemental Quarterly Financial Information (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
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 ASC 606 (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 $ 84,216 $ 63,903 $ 59,547 $ 72,740 Operating income (loss) $ 26,146 $ 175 $ 1,880 $ (3,557 ) Net income (loss) $ 24,684 $ (1,080 ) $ 934 $ (10,823 ) Net income (loss) per share, basic $ 0.39 $ (0.02 ) $ 0.01 $ (0.15 ) Net income (loss) per share, diluted $ 0.34 $ (0.02 ) $ 0.01 $ (0.15 ) Three months ended ASC 605 (in thousands) March 31, 2018 June 30, 2018 September 30, 2018 December 31, 2018 Total revenue $ 91,731 $ 95,566 $ 93,871 $ 103,894 Gross profit $ 62,689 $ 66,110 $ 66,667 $ 73,623 Operating income (loss) $ 4,270 $ 2,177 $ 8,968 $ (2,424 ) Three months ended (1) (in thousands, except per share data) March 31, 2017 June 30, 2017 September 30, 2017 December 31, 2017 Total revenue $ 76,882 $ 81,646 $ 84,938 $ 89,867 Gross profit $ 50,128 $ 54,728 $ 58,636 $ 63,250 Operating loss $ (1,990 ) $ (7,158 ) $ (20,928 ) $ (3,181 ) Net loss $ (2,188 ) $ (7,246 ) $ (29,626 ) $ (60,347 ) Net loss per share, basic $ (0.04 ) $ (0.14 ) $ (0.59 ) $ (1.03 ) Net loss per share, diluted $ (0.04 ) $ (0.14 ) $ (0.59 ) $ (1.03 ) ____________________________________________________________________ (1) The three months ended March 31, 2017, June 30, 2017, September 30, 2017 and December 31, 2017 have been reported under ASC 605 and have not been adjusted under the modified retrospective approach. See Note 3 – Revenue from contracts with customers for the effect of the adoption of ASC 606 on the Company’s consolidated financial statements.

Description of Business - Addit

Description of Business - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	Oct. 05, 2017	Jun. 30, 2018	Nov. 30, 2017	Dec. 31, 2018	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]
Entity incorporation state				Delaware
Number of shares issued and sold			9,865,004
Price per share			$ 13
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
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

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Additional Information (Detail)		Oct. 05, 2017$ / sharesshares	Dec. 31, 2018USD ($)Customer$ / sharesshares	Dec. 31, 2017USD ($)Customer$ / sharesshares	Dec. 31, 2016USD ($)Customer	Dec. 31, 2015USD ($)
Accounting Policies [Line Items]
Stock split ratio		4
Common stock, par value | $ / shares		$ 0.0001
Common stock conversion description			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.
Allowance for doubtful accounts			$ 1,150,000	$ 798,000	$ 565,000	$ 937,000
Number of individual customer accounted for 10% or more of revenue | Customer			0	0	0
Impairment losses			$ 0	$ 0	$ 0
Impairment of intangible assets			608,000	0	0
Research and development expenses	[1]		97,592,000	93,234,000	71,325,000
Advertising expenses			4,400,000	3,500,000	$ 2,500,000
Operating leases, future minimum lease payments due			$ 33,179,000
Restricted Stock Units (RSUs) [Member]
Accounting Policies [Line Items]
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]
Accounting Policies [Line Items]
Tax credit carryforward, period			3 years
Tax credit carryforward			$ 11,700,000	10,200,000
Income tax receivable [Member] | Ministry of the Economy, Finance and Industry, France [Member] | Research and Development Tax Credit Carryforward [Member]
Accounting Policies [Line Items]
Tax credit carryforward			2,600,000	3,300,000
Other long-term assets [Member] | Ministry of the Economy, Finance and Industry, France [Member] | Research and Development Tax Credit Carryforward [Member]
Accounting Policies [Line Items]
Tax credit carryforward			$ 9,100,000	$ 6,900,000
Product Concentration Risk [Member] | Sales Revenue, Net [Member] | Automotive Industry [Member]
Accounting Policies [Line Items]
Concentration of credit risk, percentage			45.00%	50.00%	50.00%
Preferred Stock [Member]
Accounting Policies [Line Items]
Capital units authorized | shares		45,000,000
Class B Common Stock [Member]
Accounting Policies [Line Items]
Common stock, par value | $ / shares			$ 0.0001	$ 0.0001
Conversion from Class B to Class A | shares		2,495,752
Capital units authorized | shares		41,203,428	41,203,428
Class B Common Stock [Member] | Maximum [Member]
Accounting Policies [Line Items]
Percentage of stock held by holders		3.00%
Class A Common Stock [Member]
Accounting Policies [Line Items]
Common stock, par value | $ / shares			$ 0.0001	$ 0.0001
Capital units authorized | shares		513,796,572	513,796,572
Class A Common Stock [Member] | Put Option [Member]
Accounting Policies [Line Items]
Put right exercise period from date of purchase				5 years
Shares issued | shares				200,000
Put right, exercise price | $ / shares				$ 12.50
[1]	The year ended December 31, 2018 has been reported under ASC 606, and the years ended December 31, 2017 and 2016 have been reported under ASC 605 and have not been adjusted under the modified retrospective approach. 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 Accoun_5

Summary of Significant Accounting Policies - Reconciliation of Cash, Cash Equivalents and Restricted Cash (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accounting Policies [Abstract]
Cash and cash equivalents	$ 35,345	$ 39,213
Restricted cash included in other long-term assets	340	365
Total cash, cash equivalents, and restricted cash shown in the statement of cash flows	$ 35,685	$ 39,578	$ 17,139	$ 14,013

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Schedule of Accounts Receivable Net (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Accounts Notes Loans And Financing Receivable Gross Allowance And Net [Abstract]
Accounts receivable, trade	$ 93,073	$ 82,185
Contract assets	3,730	4,450
Accounts receivable, net	$ 96,803	$ 86,635

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - Schedule of Allowance for Doubtful Accounts (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accounts Notes Loans And Financing Receivable Gross Allowance And Net [Abstract]
Balance, beginning of year	$ (798)	$ (565)	$ (937)
Provision charged to expense	(394)	(610)	(291)
Write-offs, net of recoveries	3	414	638
Effects of foreign currency translation	39	(37)	25
Balance, end of year	$ (1,150)	$ (798)	$ (565)

Revenue from Contracts with C_3

Revenue from Contracts with Customers - Additional Information (Details) - USD ($) $ in Thousands		3 Months Ended				12 Months Ended
		Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Cumulative effect on accumulated deficit, before tax						$ 84,600
Cumulative effect on accumulated deficit, net of tax						70,800
Accumulated deficit		$ (82,005)				(82,005)	$ (166,499)
Income tax expense	[1]					13,309	62,996	$ 3,539
Total revenue	[1]					$ 396,379	333,333	313,240
Capitalized contract cost, amortization period		4 years				4 years
Capitalized contract cost, amortization method						straight-line basis
Deferred revenue, revenue recognized						$ 53,000
Sales and Marketing Expense [Member]
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Capitalized contract cost, amortization expense						300
Prepaid and Other Current Assets [Member]
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Capitalized contract cost net, current		$ 2,000				2,000
Other long-term assets [Member]
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Capitalized contract cost net, noncurrent		200				200
Software Related Services [Member]
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Total revenue	[1]					36,945	35,397	35,770
Client Engineering Services [Member]
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Total revenue	[1]					47,852	46,510	$ 47,702
Other [Member]
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Total revenue						7,200
ASC 606 [Member]
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Accumulated deficit		82,900				82,900	$ (95,720)
Income tax expense						$ 1,000
Percentage of net revenues through indirect channels						10.00%
Total revenue		$ 103,011	$ 86,751	$ 93,360	$ 113,257
[1]	The year ended December 31, 2018 has been reported under ASC 606, and the years ended December 31, 2017 and 2016 have been reported under ASC 605 and have not been adjusted under the modified retrospective approach. 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 C_4

Revenue from Contracts with Customers - Schedule of Cumulative Impact of Adoption of ASC 606 in Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Prepaid expenses and other current assets	$ 15,491	$ 10,006
Deferred tax assets	1,373	8,351
Other long-term assets	17,288	17,019
Other accrued expenses and current liabilities	26,347	21,744
Deferred revenue, current	59,765	130,122
Deferred revenue, non-current	6,754	9,640
Other long-term liabilities	28,153	17,647
Accumulated deficit	(82,005)	(166,499)
Accumulated other comprehensive loss	(11,052)	(5,072)
ASC 606 [Member]
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Prepaid expenses and other current assets		11,595
Deferred tax assets		(4,001)
Other long-term assets		17,147
Other accrued expenses and current liabilities		22,793
Deferred revenue, current		52,477
Deferred revenue, non-current		4,377
Other long-term liabilities		18,092
Accumulated deficit	82,900	(95,720)
Adjustments for ASC 606 [Member] | ASC 606 [Member]
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Prepaid expenses and other current assets	1,798	1,589
Deferred tax assets	(12,719)	(12,352)
Other long-term assets	211	128
Other accrued expenses and current liabilities	912	1,049
Deferred revenue, current	(84,945)	(77,645)
Deferred revenue, non-current	(7,037)	(5,263)
Other long-term liabilities	517	445
Accumulated deficit	81,595	$ 70,779
Accumulated other comprehensive loss	(1,752)
Prior to Adoption of ASC 606 [Member] | ASC 606 [Member]
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Prepaid expenses and other current assets	13,693
Deferred tax assets	14,092
Other long-term assets	17,077
Other accrued expenses and current liabilities	25,435
Deferred revenue, current	144,710
Deferred revenue, non-current	13,791
Other long-term liabilities	27,636
Accumulated deficit	(163,600)
Accumulated other comprehensive loss	$ (9,300)

Revenue from Contracts with C_5

Revenue from Contracts with Customers - Schedule of Cumulative Impact of Adoption of ASC 606 in Consolidated Statement of Operations (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended												12 Months Ended
		Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017		Sep. 30, 2017		Jun. 30, 2017		Mar. 31, 2017		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenue
Revenue	[1]													$ 396,379	$ 333,333	$ 313,240
Gross profit	[1]													280,406	226,742	210,640
Operating expenses
Sales and marketing	[1]													80,277	79,958	66,086
Total operating expenses	[1]													255,762	259,999	195,193
Operating income (loss)	[1]													24,644	(33,257)	15,447
Income before income taxes	[1]													27,024	(36,411)	13,702
Income tax expense	[1]													13,309	62,996	3,539
Net income (loss)	[1]													$ 13,715	$ (99,407)	$ 10,163
Income (loss) per share:
Net income (loss) per share attributable to common stockholders, basic	[1]													$ 0.20	$ (1.89)	$ 0.21
Net income (loss) per share attributable to common stockholders, diluted	[1]													$ 0.18	$ (1.89)	$ 0.18
ASC 606 [Member]
Revenue
Revenue		$ 103,011	$ 86,751	$ 93,360	$ 113,257
Gross profit		72,740	59,547	63,903	84,216
Operating expenses
Operating income (loss)		(3,557)	1,880	175	26,146
Income tax expense														$ 1,000
Net income (loss)		$ (10,823)	$ 934	$ (1,080)	$ 24,684
Income (loss) per share:
Net income (loss) per share attributable to common stockholders, basic		$ (0.15)	$ 0.01	$ (0.02)	$ 0.39
Net income (loss) per share attributable to common stockholders, diluted		$ (0.15)	$ 0.01	$ (0.02)	$ 0.34
License [Member]
Revenue
Revenue	[1]													207,164
Prior to Adoption of ASC 606 [Member]
Revenue
Revenue		$ 103,894	$ 93,871	$ 95,566	$ 91,731	$ 89,867	[2]	$ 84,938	[2]	$ 81,646	[2]	$ 76,882	[2]
Gross profit		73,623	66,667	66,110	62,689	63,250	[2]	58,636	[2]	54,728	[2]	50,128	[2]
Operating expenses
Operating income (loss)		$ (2,424)	$ 8,968	$ 2,177	$ 4,270	(3,181)	[2]	(20,928)	[2]	(7,158)	[2]	(1,990)	[2]
Net income (loss)	[2]					$ (60,347)		$ (29,626)		$ (7,246)		$ (2,188)
Income (loss) per share:
Net income (loss) per share attributable to common stockholders, basic	[2]					$ (1.03)		$ (0.59)		$ (0.14)		$ (0.04)
Net income (loss) per share attributable to common stockholders, diluted	[2]					$ (1.03)		$ (0.59)		$ (0.14)		$ (0.04)
Prior to Adoption of ASC 606 [Member] | ASC 606 [Member]
Revenue
Gross profit														269,089
Operating expenses
Sales and marketing														80,613
Total operating expenses														256,098
Operating income (loss)														12,991
Income before income taxes														15,371
Income tax expense														12,472
Net income (loss)														$ 2,899
Income (loss) per share:
Net income (loss) per share attributable to common stockholders, basic														$ 0.04
Net income (loss) per share attributable to common stockholders, diluted														$ 0.04
Prior to Adoption of ASC 606 [Member] | License [Member] | ASC 606 [Member]
Revenue
Revenue														$ 195,847
Adjustments for ASC 606 [Member] | ASC 606 [Member]
Revenue
Gross profit														11,317
Operating expenses
Sales and marketing														(336)
Total operating expenses														(336)
Operating income (loss)														11,653
Income before income taxes														11,653
Income tax expense														837
Net income (loss)														$ 10,816
Income (loss) per share:
Net income (loss) per share attributable to common stockholders, basic														$ 0.16
Net income (loss) per share attributable to common stockholders, diluted														$ 0.14
Adjustments for ASC 606 [Member] | License [Member] | ASC 606 [Member]
Revenue
Revenue														$ 11,317
[1]	The year ended December 31, 2018 has been reported under ASC 606, and the years ended December 31, 2017 and 2016 have been reported under ASC 605 and have not been adjusted under the modified retrospective approach. See Note 3 – Revenue from contracts with customers for the effect of the adoption of ASC 606 on the Company’s consolidated financial statements.
[2]	The three months ended March 31, 2017, June 30, 2017, September 30, 2017 and December 31, 2017 have been reported under ASC 605 and have not been adjusted under the modified retrospective approach. 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 C_6

Revenue from Contracts with Customers - Schedule of Disaggregation of Revenue (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disaggregation Of Revenue [Line Items]
Total revenue	[1]	$ 396,379	$ 333,333	$ 313,240
Perpetual Licenses
Disaggregation Of Revenue [Line Items]
Total revenue		38,255
Software [Member]
Disaggregation Of Revenue [Line Items]
Total revenue	[1]	304,361	$ 244,817	$ 223,818
Term Licenses [Member]
Disaggregation Of Revenue [Line Items]
Total revenue		168,909
Maintenance [Member]
Disaggregation Of Revenue [Line Items]
Total revenue		86,150
Professional Services and Other [Member]
Disaggregation Of Revenue [Line Items]
Total revenue		$ 11,047
[1]	The year ended December 31, 2018 has been reported under ASC 606, and the years ended December 31, 2017 and 2016 have been reported under ASC 605 and have not been adjusted under the modified retrospective approach. 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 - Additional Infor

Acquisitions - Additional Information (Detail) $ / shares in Units, $ in Thousands, € in Millions	Nov. 05, 2018USD ($)$ / shares	Oct. 31, 2018USD ($)shares	Sep. 28, 2017USD ($)shares	May 30, 2018USD ($)	May 30, 2018EUR (€)	Apr. 30, 2018USD ($)	May 31, 2017USD ($)shares	Dec. 31, 2018USD ($)$ / shares	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Business Acquisition [Line Items]
Business combination, consideration transferred, outstanding equity award								$ 8,681	$ 8,712
Goodwill								210,532	62,706	$ 36,625
Acquired intellectual property assets								$ 2,727	$ 2,120	$ 154
Datawatch Corporation [Member]
Business Acquisition [Line Items]
Business acquisition purchase price | $ / shares	$ 13.10							$ 13.10
Business acquisition, consideration								$ 183,400
Business combination, consideration transferred value								168,200
Business combination, consideration transferred, liabilities incurred								500
Business combination, consideration transferred, outstanding equity award								6,700
Payments of outstanding debt								8,000
Business Acquisition, Transaction Costs								$ 10,400
Business combination, pre-combination expense and consideration transferred	$ 500
Business combination, consideration allocated to future services	3,400
Fair value of consideration transferred	183,427
Goodwill	$ 131,351
Datawatch Corporation [Member] | Restricted Stock Units (RSUs) [Member]
Business Acquisition [Line Items]
Business acquisition purchase price | $ / shares	$ 13.10
Business combination, consideration transferred value	$ 3,900
Business combination, consideration transferred, outstanding equity award	$ 6,700
SIMSOLID Corporation [Member]
Business Acquisition [Line Items]
Business acquisition, consideration		$ 12,000
Fair value of consideration transferred		$ 22,139
Business acquisition, shares issued | shares		145,000
Debt conversion, Class A common stock shares issued | shares		41,537
Goodwill		$ 19,470
FluiDyna GmbH [Member]
Business Acquisition [Line Items]
Fair value of consideration transferred				$ 2,700	€ 2.2
Business combination, prior equity interests				24.00%
Finite-lived intangibles				$ 2,100
Goodwill				$ 1,800
CANDI Cortrols, Inc. [Member]
Business Acquisition [Line Items]
Acquired intellectual property assets						$ 2,400
Runtime [Member]
Business Acquisition [Line Items]
Business acquisition, consideration			$ 19,400
Business combination, consideration transferred, liabilities incurred			9,400
Fair value of consideration transferred			25,508
Goodwill			$ 17,487
Business acquisition, percentage of interest acquired			100.00%
Business acquisition, working capital adjustment			$ 700
Runtime [Member] | Class A Common Stock [Member]
Business Acquisition [Line Items]
Business acquisition, shares issued | shares			708,000
Carriots [Member]
Business Acquisition [Line Items]
Business acquisition, consideration							$ 3,600
Business combination, consideration transferred, liabilities incurred							2,700
Fair value of consideration transferred							6,657
Goodwill							$ 4,941
Business acquisition, percentage of interest acquired							100.00%
Carriots [Member] | Class A Common Stock [Member]
Business Acquisition [Line Items]
Business acquisition, shares issued | shares							80,000

Acquisitions - Summary of Amoun

Acquisitions - Summary of Amounts of Identified Assets Acquired and Liabilities Assumed at the Acquisition Date (Detail) - USD ($) $ in Thousands	Nov. 05, 2018	Oct. 31, 2018	Sep. 28, 2017	May 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Recognized amounts of identifiable assets acquired and liabilities assumed:
Goodwill					$ 210,532	$ 62,706	$ 36,625
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	10,784
Other assets	3,055
Property and equipment	980
Accounts payable and other liabilities	(5,393)
Deferred revenue	(4,100)
Other long-term liabilities	(7,928)
Total net identifiable assets acquired and liabilities assumed	52,076
Goodwill	131,351
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	$ 16,400
SIMSOLID Corporation [Member]
Business Acquisition [Line Items]
Fair value of consideration transferred		$ 22,139
Recognized amounts of identifiable assets acquired and liabilities assumed:
Total net identifiable assets acquired and liabilities assumed		2,669
Current assets		135
Current liabilities		(141)
Long term liabilities		(960)
Goodwill		19,470
SIMSOLID Corporation [Member] | Trade Names [Member]
Recognized amounts of identifiable assets acquired and liabilities assumed:
Indefinite-lived intangibles		344
SIMSOLID Corporation [Member] | Developed Technology [Member]
Recognized amounts of identifiable assets acquired and liabilities assumed:
Finite-lived intangibles		$ 3,291
Runtime [Member]
Business Acquisition [Line Items]
Fair value of consideration transferred			$ 25,508
Recognized amounts of identifiable assets acquired and liabilities assumed:
Cash			564
Accounts receivable			2,257
Deferred tax assets			1,713
Other assets			257
Accounts payable and other liabilities			(1,000)
Deferred revenue			(1,925)
Total net identifiable assets acquired and liabilities assumed			8,021
Deferred tax liabilities			(4,645)
Goodwill			17,487
Runtime [Member] | Trade Names [Member]
Recognized amounts of identifiable assets acquired and liabilities assumed:
Indefinite-lived intangibles			440
Runtime [Member] | Developed Technology [Member]
Recognized amounts of identifiable assets acquired and liabilities assumed:
Finite-lived intangibles			7,870
Runtime [Member] | Customer Relationships [Member]
Recognized amounts of identifiable assets acquired and liabilities assumed:
Finite-lived intangibles			$ 2,490
Carriots [Member]
Business Acquisition [Line Items]
Fair value of consideration transferred				$ 6,657
Recognized amounts of identifiable assets acquired and liabilities assumed:
Deferred tax assets				394
Other assets				472
Accounts payable and other liabilities				(1,015)
Total net identifiable assets acquired and liabilities assumed				1,716
Goodwill				4,941
Carriots [Member] | Trade Names [Member]
Recognized amounts of identifiable assets acquired and liabilities assumed:
Indefinite-lived intangibles				252
Carriots [Member] | Developed Technology [Member]
Recognized amounts of identifiable assets acquired and liabilities assumed:
Finite-lived intangibles				1,317
Carriots [Member] | Customer Relationships [Member]
Recognized amounts of identifiable assets acquired and liabilities assumed:
Finite-lived intangibles				$ 296

Acquisitions - Summary of Amo_2

Acquisitions - Summary of Amounts of Identified Assets Acquired and Liabilities Assumed at the Acquisition Date (Parenthetical) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 13, 2018
Developed Technology [Member]
Business Acquisition [Line Items]
Weighted-average useful life of acquired finite-lived intangible assets		4 years
Customer Relationships [Member]
Business Acquisition [Line Items]
Weighted-average useful life of acquired finite-lived intangible assets		7 years
Datawatch Corporation [Member] | Software [Member]
Business Acquisition [Line Items]
Goodwill deductible for tax purposes			$ 0.8
Datawatch Corporation [Member] | Developed Technology [Member]
Business Acquisition [Line Items]
Weighted-average useful life of acquired finite-lived intangible assets	6 years
Datawatch Corporation [Member] | Customer Relationships [Member]
Business Acquisition [Line Items]
Weighted-average useful life of acquired finite-lived intangible assets	10 years
Runtime [Member] | Developed Technology [Member]
Business Acquisition [Line Items]
Weighted-average useful life of acquired finite-lived intangible assets	4 years
Runtime [Member] | Customer Relationships [Member]
Business Acquisition [Line Items]
Weighted-average useful life of acquired finite-lived intangible assets	7 years
Carriots [Member] | Developed Technology [Member]
Business Acquisition [Line Items]
Weighted-average useful life of acquired finite-lived intangible assets	4 years
Carriots [Member] | Customer Relationships [Member]
Business Acquisition [Line Items]
Weighted-average useful life of acquired finite-lived intangible assets	7 years

Acquisitions - Schedule of Pro

Acquisitions - Schedule of Pro Forma Financial Information (Detail) - Datawatch Corporation [Member] - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Total revenue	$ 435,414	$ 363,906
Net income (loss)	$ 7,613	$ (115,010)
Net income (loss) per share attributable to common stockholders, basic	$ 0.11	$ (2.19)
Net income (loss) per share attributable to common stockholders, diluted	$ 0.10	$ (2.19)

Property and Equipment, Net - S

Property and Equipment, Net - Summary of Property and Equipment (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 70,580	$ 68,500
Less: accumulated depreciation and amortization	40,427	37,054
Property and equipment, net	30,153	31,446
Land [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 7,994	7,994
Property, Plant and Equipment, Estimated Useful Lives	Indefinite
Building and Improvements [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 13,120	15,185
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	$ 34,582	32,103
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	$ 7,958	6,751
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	$ 6,926	$ 6,467
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

Property and Equipment, Net -_2

Property and Equipment, Net - Summary of Property and Equipment (Parenthetical) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
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
Equipment [Member]
Property, Plant and Equipment [Line Items]
Carrying value of equipment under capital lease obligation	$ 2	$ 1.1

Property and Equipment, Net - A

Property and Equipment, Net - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Nov. 30, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jun. 30, 2018
Property, Plant and Equipment [Line Items]
Purchase of property, plant and equipment	$ 4,000
Book value of building held for sale, net		$ 30,153	$ 31,446
Gain on sale of building		4,400
Depreciation expense, including amortization of assets under capital lease		$ 7,000	$ 6,300	$ 6,700
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

Goodwill and Other Intangible_3

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, 2018	Dec. 31, 2017
Goodwill And Intangible Assets Disclosure [Abstract]
Beginning Balance	$ 62,706	$ 36,625
Acquisitions	152,630	22,420
Effects of foreign currency translation and other	(4,804)	3,661
Ending Balance	$ 210,532	$ 62,706

Goodwill and Other Intangible_4

Goodwill and Other Intangible Assets - Schedule of Other Intangible Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Summary Of Other Intangible Assets [Line Items]
Gross carrying amount	$ 83,061	$ 37,884
Accumulated amortization	22,882	16,161
Net carrying amount	60,179	21,723
Gross carrying amount	92,718	40,622
Accumulated amortization	22,882	16,161
Net carrying amount	69,836	$ 24,461
Developed Technology [Member]
Summary Of Other Intangible Assets [Line Items]
Weighted-average useful life of acquired finite-lived intangible assets		4 years
Gross carrying amount	54,530	$ 25,947
Accumulated amortization	15,517	9,909
Net carrying amount	$ 39,013	$ 16,038
Developed Technology [Member] | Minimum [Member]
Summary Of Other Intangible Assets [Line Items]
Weighted-average useful life of acquired finite-lived intangible assets	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
Customer Relationships [Member]
Summary Of Other Intangible Assets [Line Items]
Weighted-average useful life of acquired finite-lived intangible assets		7 years
Gross carrying amount	$ 28,422	$ 11,794
Accumulated amortization	7,309	6,195
Net carrying amount	$ 21,113	$ 5,599
Customer Relationships [Member] | Minimum [Member]
Summary Of Other Intangible Assets [Line Items]
Weighted-average useful life of acquired finite-lived intangible assets	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
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	$ 109	$ 143
Accumulated amortization	56	57
Net carrying amount	53	86
Trade Names [Member]
Summary Of Other Intangible Assets [Line Items]
Net carrying amount	$ 9,657	$ 2,738

Goodwill and Other Intangible_5

Goodwill and Other Intangible Assets - Additional Information (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Goodwill And Intangible Assets Disclosure [Abstract]
Amortization of intangible assets	[1]	$ 7,739	$ 5,448	$ 3,322
[1]	The year ended December 31, 2018 has been reported under ASC 606, and the years ended December 31, 2017 and 2016 have been reported under ASC 605 and have not been adjusted under the modified retrospective approach. 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_6

Goodwill and Other Intangible Assets - Summary of Estimated Amortization Expense (Detail) $ in Thousands	Dec. 31, 2018USD ($)
Goodwill And Intangible Assets Disclosure [Abstract]
December 31, 2019	$ 13,880
December 31, 2020	12,959
December 31, 2021	10,590
December 31, 2022	7,378
December 31, 2023	$ 6,627

Debt - Schedule of Carrying Val

Debt - Schedule of Carrying Value of Debt (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Total debt	$ 31,838	$ 410
Less: unamortized debt issuance costs	90
Current portion of long-term debt	331	232
Long-term debt, net of current portion	31,417	178
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Total debt	30,950
Capital Lease Obligations [Member]
Debt Instrument [Line Items]
Total debt	813	207
Other Borrowings [Member]
Debt Instrument [Line Items]
Total debt	$ 75	$ 203

Debt - Additional Information (

Debt - Additional Information (Detail) - USD ($)	Nov. 03, 2017	Oct. 18, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Oct. 31, 2018
Debt Instrument [Line Items]
Payments on long-term debt			$ 126,000	$ 59,869,000	$ 16,232,000
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
2017 Credit Agreement [Member] | JPMorgan Chase Bank, N.A. [Member]
Debt Instrument [Line Items]
Aggregate commitment amount under credit facility		$ 100,000,000	$ 150,000,000	$ 100,000,000
Maturity date		Oct. 18, 2022
Increase in line of credit borrowing capacity						$ 50,000,000
Increase in unrestricted domestic cash		$ 20,000,000
Maximum leverage ratio		3.00%
2017 Credit Agreement [Member] | JPMorgan Chase Bank, N.A. [Member] | 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%
2017 Credit Agreement [Member] | JPMorgan Chase Bank, N.A. [Member] | Maximum [Member]
Debt Instrument [Line Items]
Commitment fees on unused portion of the Revolving Credit Facility			0.30%
2017 Credit Agreement [Member] | JPMorgan Chase Bank, N.A. [Member] | Federal Funds Effective Swap Rate [Member]
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate		0.50%
2017 Credit Agreement [Member] | JPMorgan Chase Bank, N.A. [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate		1.00%
2017 Credit Agreement [Member] | JPMorgan Chase Bank, N.A. [Member] | Swingline Loans [Member]
Debt Instrument [Line Items]
Aggregate commitment amount under credit facility		$ 5,000,000
2017 Credit Agreement [Member] | JPMorgan Chase Bank, N.A. [Member] | Swingline Loans [Member] | Minimum [Member]
Debt Instrument [Line Items]
Applicable margin for borrowings under new credit facility		0.25%
2017 Credit Agreement [Member] | JPMorgan Chase Bank, N.A. [Member] | Swingline Loans [Member] | Maximum [Member]
Debt Instrument [Line Items]
Applicable margin for borrowings under new credit facility		1.00%
2017 Credit Agreement [Member] | JPMorgan Chase Bank, N.A. [Member] | Eurodollar Loans [Member] | Minimum [Member]
Debt Instrument [Line Items]
Applicable margin for borrowings under new credit facility		1.25%
2017 Credit Agreement [Member] | JPMorgan Chase Bank, N.A. [Member] | Eurodollar Loans [Member] | Maximum [Member]
Debt Instrument [Line Items]
Applicable margin for borrowings under new credit facility		2.00%
2017 Credit Agreement [Member] | JPMorgan Chase Bank, N.A. [Member] | Letter of Credit [Member]
Debt Instrument [Line Items]
Aggregate commitment amount under credit facility		$ 5,000,000
Secured Credit Agreement
Debt Instrument [Line Items]
Payments on long-term debt	$ 93,100,000
Secured Credit Agreement | JPMorgan Chase Bank, N.A. [Member]
Debt Instrument [Line Items]
Loan outstanding			$ 31,000,000
Amount available for future borrowing			$ 119,000,000
Weighted Average Interest Rate on borrowings			0.46%
Secured Credit Agreement | JPMorgan Chase Bank, N.A. [Member] | Term Loan A [Member]
Debt Instrument [Line Items]
Amount available under secured credit agreement		65,000,000
Secured Credit Agreement | JPMorgan Chase Bank, N.A. [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Loan outstanding					84,900,000
Amount available for future borrowing					$ 32,600,000
Amount available under secured credit agreement		60,000,000
Secured Credit Agreement | JPMorgan Chase Bank, N.A. [Member] | Revolving Credit Facility [Member] | Swingline Subfacility and Letter of Credit Subfacility [Member]
Debt Instrument [Line Items]
Amount available under secured credit agreement		$ 5,000,000

Debt - Scheduled Maturities of

Debt - Scheduled Maturities of Long Term Debt (Detail) $ in Thousands	Dec. 31, 2018USD ($)
Maturities Of Long Term Debt [Abstract]
2,019	$ 75
2,020	0
2,021	0
2,022	30,950
2,023	0
Total	$ 31,025

Other Liabilities - Summary of

Other Liabilities - Summary of Other Accrued Expenses and Current Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Other Liabilities Disclosure [Abstract]
Accrued VAT	$ 4,536	$ 3,916
Income taxes payable	4,458	3,724
Accrued professional fees	3,165	2,500
Accrued royalties	2,613	2,037
Billings in excess of cost	1,504	832
Defined contribution plan liabilities	1,376	1,274
Government grants	915	712
Non-income tax liabilities	853	1,343
Related party liabilities		119
Other current liabilities	6,927	5,287
Total	$ 26,347	$ 21,744

Other Liabilities - Summary o_2

Other Liabilities - Summary of Other Long-term Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Other Liabilities Disclosure [Abstract]
Pension and other post retirement liabilities	$ 9,111	$ 7,670
Deferred tax liabilities	7,736	1,620
Other liabilities	11,306	8,357
Total	$ 28,153	$ 17,647

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Changes in the Fair Value of Company's Level 3 Financial Liabilities (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2017USD ($)
Liability for Class A Redeemable Common Shares [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	$ 10,632
Exercise of stock options	432
Change in fair value	19,223
Modification to stock options as a result of the Company's IPO	(30,287)
Liability for Stock-Based Compensation Awards [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance	11,604
Exercise of stock options	(411)
Forfeitures of stock options	(157)
Change in fair value	25,191
Modification to stock options as a result of the Company's IPO	$ (36,227)

Fair Value Measurements - Sum_2

Fair Value Measurements - Summary of Changes in the Fair Value of Company's Level 3 Financial Liabilities (Parenthetical) (Detail) - Liability for Class A Redeemable Common Shares [Member] - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial liabilities		$ 10,632
2001 ISO and NQSO Plan [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Financial liabilities	$ 66,500

Financial Instruments - Additio

Financial Instruments - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Other Long-term Liabilities [Member]
Derivative [Line Items]
Fair value of derivative instruments liability	$ 100,000	$ 200,000
Interest Rate Swap [Member]
Derivative [Line Items]
Derivatives outstanding notional value	$ 4,500,000	4,500,000
Derivatives maturity date	Dec. 23, 2019
Foreign Exchange Contract [Member]
Derivative [Line Items]
Derivatives outstanding notional value	$ 0	$ 0

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2018Vote$ / sharesshares	Dec. 31, 2017$ / sharesshares	Dec. 31, 2016$ / shares	Oct. 05, 2017$ / sharesshares
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]
Capital units authorized | shares	513,796,572			513,796,572
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]
Capital units authorized | shares	41,203,428			41,203,428
Common stock, par value | $ / shares	$ 0.0001	$ 0.0001
Number of votes entitled per share | Vote	10

Stock-based Compensation - Addi

Stock-based Compensation - Additional Information (Detail) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Sep. 30, 2017USD ($)	Dec. 31, 2018USD ($)Installment$ / sharesshares	Dec. 31, 2017USD ($)$ / sharesshares	Dec. 31, 2016USD ($)	Sep. 27, 2017shares	Dec. 31, 2012shares	Dec. 31, 2001shares
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		$ 26,347	$ 21,744
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		2 years
Other accrued expenses and current liabilities		$ 600
Liability for Class A Redeemable Common Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Financial liabilities				$ 10,632
NSO Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options, outstanding | shares		4,337,856	6,441,972
Exercise price stock options outstanding | $ / shares		$ 0.000025	$ 0.000025
Contractual term		35 years
ISO Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of options, outstanding | shares		532,220	888,864
Exercise price stock options outstanding | $ / shares			$ 0.67
Contractual term		10 years
Intrinsic value of options exercised		$ 5,200	$ 25,600	2,700
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		1,541,165	2,183,127
Exercise price stock options outstanding | $ / shares		$ 4.12	$ 3.74
Contractual term		10 years
Total requisite service period of awards		4 years
Compensation expense		$ 600	$ 700	$ 600
Compensation cost related to nonvested awards not yet recognized		$ 900
Weighted average period of recognition		2 years 8 months 12 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] | 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		$ 5,300
Weighted average period of recognition		4 years
Weighted average grant date fair value of RSUs | $ / shares		$ 30.96
Number of vesting equal annual installments | Installment		4
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 - Summ

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, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Number of options, Outstanding, Beginning Balance	6,441,972
Number of options, Exercised	(2,104,116)
Number of options, Forfeited	0
Number of options, Outstanding and exercisable, Ending Balance	4,337,856
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		19 years
Weighted average remaining contractual term (years), Outstanding and exercisable	18 years
Aggregate intrinsic value, Outstanding		$ 154.1
Aggregate intrinsic value, Outstanding and exercisable	$ 119.6

Stock-based Compensation - Su_2

Stock-based Compensation - Summary of Stock Option Activity under ISO Plan (Detail) - ISO Plan [Member] - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Number of options, Outstanding, Beginning Balance	888,864
Number of options, Exercised	(356,644)
Number of options, Forfeited	0
Number of options, Outstanding and exercisable, Ending Balance	532,220
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	$ 0.67
Weighted average exercise price per share, Exercised	0.69
Weighted average exercise price per share, Forfeited	0
Weighted average exercise price per share, Outstanding and exercisable, Ending Balance	$ 0.65
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted average remaining contractual term (years), Outstanding		2 years 6 months
Weighted average remaining contractual term (years), Outstanding and exercisable	1 year 4 months 24 days
Aggregate intrinsic value, Outstanding		$ 20.7
Aggregate intrinsic value, Outstanding and exercisable	$ 14.3

Stock-based Compensation - Su_3

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, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Number of options, Outstanding, Beginning Balance	2,183,127
Number of options, Granted	0
Number of options, Exercised	(623,119)
Number of options, Forfeited	(18,843)
Number of options, Outstanding, Ending Balance	1,541,165	2,183,127
Number of options, Exercisable	975,291
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	$ 3.74
Granted	0
Weighted average exercise price per share, Exercised	2.76
Weighted average exercise price per share, Forfeited	4.68
Weighted average exercise price per share, Outstanding, Ending Balance	4.12	$ 3.74
Weighted average exercise price per share, Exercisable	$ 3.70
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Weighted average remaining contractual term (years), Outstanding	6 years 10 months 24 days	7 years 3 months 19 days
Weighted average remaining contractual term (years), Exercisable	6 years 1 month 6 days
Aggregate intrinsic value, Outstanding	$ 36.2	$ 44.1
Aggregate intrinsic value, Exercisable	$ 23.3

Stock-based Compensation - Su_4

Stock-based Compensation - Summary of Restricted Stock Units Awarded (Detail) - Restricted Stock Units (RSUs) [Member]	12 Months Ended
	Dec. 31, 2018shares
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Weighted average remaining contractual term (years), Outstanding	2 years
2017 Plan [Member]
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	0
Number of RSUs, Granted	228,201
Number of RSUs, Vested	(1,000)
Number of RSUs, Forfeited	(21,140)
Number of RSUs, Outstanding Ending Balance	206,061

Stock-based Compensation - Weig

Stock-based Compensation - Weighted Average Assumptions To Calculate Fair Value of Options Granted (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	34.00%	37.00%
Risk-free interest rate	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	$ 1.42
Expected term (in years)	5 years 9 months	5 years 9 months
Risk-free interest rate		1.37%
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant date fair value per share	$ 1.94	$ 1.65
Expected term (in years)	6 years 2 months 30 days	6 years 2 months 30 days
Risk-free interest rate		1.79%

Stock-based Compensation - Su_5

Stock-based Compensation - Summary of Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended			12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense	$ 8,000	$ 25,300	$ 11,200	$ 3,339	$ 47,281	$ 5,132
Cost of Revenue - Software [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense				31	350	22
Research and development [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense				740	12,540	1,370
Sales and marketing [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense				910	7,693	775
General and administrative [Member]
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation expense				$ 1,658	$ 26,698	$ 2,965

Other (Income) Expense, Net - S

Other (Income) Expense, Net - Schedule of Other (Income) Expense, Net (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Other Income And Expenses [Abstract]
Foreign exchange (gain) loss		$ (626)	$ 1,254	$ (271)
Other		(1,954)	(260)	(249)
Other (income) expense, net	[1]	$ (2,580)	$ 994	$ (520)
[1]	The year ended December 31, 2018 has been reported under ASC 606, and the years ended December 31, 2017 and 2016 have been reported under ASC 605 and have not been adjusted under the modified retrospective approach. 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 In

Income Taxes - Components of Income (Loss) Before Income Taxes (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
U.S		$ 4,228	$ (49,761)	$ (2,225)
Non-U.S		22,796	13,350	15,927
Income (loss) before income taxes	[1]	$ 27,024	$ (36,411)	$ 13,702
[1]	The year ended December 31, 2018 has been reported under ASC 606, and the years ended December 31, 2017 and 2016 have been reported under ASC 605 and have not been adjusted under the modified retrospective approach. 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 - Significant Comp

Income Taxes - Significant Components of Income Tax Expense (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current
U.S. Federal		$ 2	$ 0	$ 0
Non-U.S.		12,552	10,290	9,413
U.S. State and Local		(8)	135	202
Total current		12,546	10,425	9,615
Deferred
U.S. Federal		1,714	54,130	(5,358)
Non-U.S.		(934)	(1,306)	(610)
U.S. State and Local		(17)	(253)	(108)
Total deferred		763	52,571	(6,076)
Income tax expense	[1]	$ 13,309	$ 62,996	$ 3,539
[1]	The year ended December 31, 2018 has been reported under ASC 606, and the years ended December 31, 2017 and 2016 have been reported under ASC 605 and have not been adjusted under the modified retrospective approach. 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 - Reconciliation o

Income Taxes - Reconciliation of Income Taxes Calculated at U.S. Federal Statutory Income Tax Rate (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
U.S. federal statutory rate		21.00%	35.00%	35.00%
Income taxes at U.S. federal statutory rate		$ 5,675	$ (12,744)	$ 4,796
Foreign income taxes at rates other than the federal statutory rate		2,096	373	(584)
U.S. state and local income taxes, net of U.S. federal tax benefit		(3,446)	(155)	94
U.S. Tax Cut and Jobs Act: transition tax, net of foreign tax credits			4,187
Global intangible low-taxed income		6,587
Change in valuation allowance		16,725	47,429
Foreign withholding taxes		5,103	4,181	4,235
Foreign dividends				5,077
U.S. foreign tax credit		(4,564)	(4,154)	(8,786)
Research and development tax credit		(2,819)	(2,999)	(2,696)
Domestic production activities deduction				(840)
Non-deductible stock-based compensation		(14,964)	10,871	2,064
Meals & entertainment		181	358	235
Other		672	(163)	(91)
Deferred tax on investment in subsidiary				(264)
Uncertain tax positions		903	446	299
Acquisition costs		503
Tax law changes		657	15,366
Income tax expense	[1]	$ 13,309	$ 62,996	$ 3,539
[1]	The year ended December 31, 2018 has been reported under ASC 606, and the years ended December 31, 2017 and 2016 have been reported under ASC 605 and have not been adjusted under the modified retrospective approach. 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 - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Line Items]
U.S. Federal statutory income tax rate		21.00%	35.00%	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
Accumulated deficit		(82,005)	(166,499)
Gross unrecognized tax benefits recognized would affect the effective tax rate		17,100
Scenario, Forecast [Member]
Income Tax Disclosure [Line Items]
Change in unrecognized tax benefits that will impact effective tax rate	$ 400
ASC 606 [Member]
Income Tax Disclosure [Line Items]
Accumulated deficit		82,900	(95,720)
Valuation Allowance of Deferred Tax Assets [Member]
Income Tax Disclosure [Line Items]
Other		5,045	$ 2,749	$ 1,731
Valuation allowance against deferred taxes recorded for business combinations		12,600
Valuation Allowance of Deferred Tax Assets [Member] | ASC 606 [Member]
Income Tax Disclosure [Line Items]
Accumulated deficit		$ (7,400)

Income Taxes - Schedule of Defe

Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Deferred revenue	$ 3,063	$ 19,569
Net operating loss carryforwards	37,549	7,601
Tax credit carryforwards	30,516	22,191
Stock-based compensation	6,858	8,922
Capitalized research and development	8,266	8,798
Accrued expenses		648
Employee benefits	4,825	3,931
Other	1,777	1,905
Total gross deferred tax assets	92,854	73,565
Less: valuation allowances	(76,101)	(54,331)
Net deferred tax assets	16,753	19,234
Deferred tax liabilities:
Prepaid royalties	7,687	6,925
Property and equipment and intangibles	13,945	4,567
Deferred tax on investment in subsidiary	329	272
Other	1,155	739
Total deferred tax liabilities	23,116	12,503
Total net deferred tax assets		$ 6,731
Total net deferred tax liabilities	$ (6,363)

Income Taxes - Summary of Chang

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, 2018	Dec. 31, 2017	Dec. 31, 2016
Valuation Allowance [Line Items]
Beginning balance	$ 54,331	$ 4,153	$ 2,452
Additions charged to expense	16,725	47,429	177
Deductions			(207)
Other	5,045	2,749	1,731
Ending balance	$ 76,101	$ 54,331	$ 4,153

Income Taxes - Operating Loss a

Income Taxes - Operating Loss and Tax Credit Carryforwards (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)
Operating Loss and Tax Credit Carryforward [Line Items]
Foreign loss carryforwards, expiration year	Indefinite
U.S. foreign tax credits, expiration year	2,028
U.S. foreign tax credits	$ 6,182
Total operating loss and tax credit carryforwards	68,065
Foreign Tax Authority [Member]
Operating Loss and Tax Credit Carryforward [Line Items]
Foreign loss carryforwards	$ 8,030
General Business Tax Credit Carryforward [Member]
Operating Loss and Tax Credit Carryforward [Line Items]
U.S. general business credits and loss carryforwards, expiration year	2019-Indefinite
Foreign loss carryforwards	$ 53,853

Income Taxes - Reconciliation_2

Income Taxes - Reconciliation of Beginning and Ending Amounts of Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Unrecognized tax benefits-January 1	$ 6,157	$ 5,604	$ 5,305
Additions for tax positions of current period	234	634	299
Additions for tax positions of prior periods	10,866
Reductions for tax positions of prior periods	(100)	(81)
Reductions due to statute of limitations	(60)
Unrecognized tax benefits—December 31	$ 17,097	$ 6,157	$ 5,604

Income (Loss) Per Share - Compu

Income (Loss) Per Share - Computation of Numerators and Denominators Used Basic and Diluted (Loss) Income Per Share Amounts (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Numerator:
Net income (loss)	[1]	$ 13,715	$ (99,407)	$ 10,163
Denominator:
Denominator for basic income (loss) per share— weighted average shares	[1]	67,468	52,466	48,852
Effect of dilutive securities, stock options and RSUs		7,410		9,004
Denominator for dilutive income (loss) per share	[1]	74,878	52,466	57,856
Net income (loss) per share attributable to common stockholders, basic	[1]	$ 0.20	$ (1.89)	$ 0.21
Net income (loss) per share attributable to common stockholders, diluted	[1]	$ 0.18	$ (1.89)	$ 0.18
[1]	The year ended December 31, 2018 has been reported under ASC 606, and the years ended December 31, 2017 and 2016 have been reported under ASC 605 and have not been adjusted under the modified retrospective approach. 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 (Loss) Per Share - Addit

Income (Loss) Per Share - Additional Information (Detail) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Earnings Per Share [Abstract]
Anti-dilutive shares excluded from computation of (loss) income per share	0	10,200,000	0

Retirement Benefits - Additiona

Retirement Benefits - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Compensation And Retirement Disclosure [Abstract]
Funded percentage	80.00%
Defined Benefit Plan, Contributions by Employer	$ 1.3	$ 1.1	$ 1.1
Net benefit cost	1.2	1.2	0.9
Benefit obligation benefits paid	0.4	0.2	$ 0.2
Accumulated benefit obligation	6	5.5
Defined benefit plan assets	0.9
Defined benefit plan funded	$ 9.6	$ 8

Retirement Benefits - Schedule

Retirement Benefits - Schedule of Pension Benefits Obligation (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Funded Status Of Plan [Abstract]
Accrued compensation and benefits	$ 513	$ 368
Other long-term liabilities	9,111	7,670
Components of pension benefits	$ 9,624	$ 8,038

Retirement Benefits - Schedul_2

Retirement Benefits - Schedule of Estimated Future Benefit Payments (Detail) $ in Thousands	Dec. 31, 2018USD ($)
Defined Benefit Plan Estimated Future Benefit Payments [Abstract]
December 31, 2019	$ 537
December 31, 2020	356
December 31, 2021	283
December 31, 2022	337
December 31, 2023	519
Next five years	$ 2,484

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Loss - Components of Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	$ 60,591	$ (34,653)	$ (42,039)
Other comprehensive income (loss) before reclassification	(5,121)	2,138	(691)
Amounts reclassified from accumulated other comprehensive loss	(1,177)	54
Tax effects	318		135
Total other comprehensive (loss) income	(5,980)	2,192	(556)
Ending balance	286,782	60,591	(34,653)
Foreign Currency Translation [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(3,374)	(5,725)	(5,745)
Other comprehensive income (loss) before reclassification	(5,211)	2,351	80
Tax effects			(60)
Total other comprehensive (loss) income	(5,211)	2,351	20
Ending balance	(8,585)	(3,374)	(5,725)
Retirement Related Benefit Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(1,698)	(1,539)	(963)
Other comprehensive income (loss) before reclassification	90	(213)	(771)
Amounts reclassified from accumulated other comprehensive loss	(1,177)	54
Tax effects	318		195
Total other comprehensive (loss) income	(769)	(159)	(576)
Ending balance	(2,467)	(1,698)	(1,539)
Accumulated Other Comprehensive Loss [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(5,072)	(7,264)	(6,708)
Ending balance	$ (11,052)	$ (5,072)	$ (7,264)

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Detail) $ in Thousands	1 Months Ended		12 Months Ended
	Feb. 28, 2017USD ($)	Feb. 28, 2016USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)Installmentshares
Related Party Transaction [Line Items]
Purchase of noncontrolling interests				$ (29)
Payment to acquire business			$ 203,438	15,582	$ 6,499
Obligations to related parties, current				119
Receivable eliminated period			2018-05
Other accrued expenses and current liabilities [Member]
Related Party Transaction [Line Items]
Obligations to related parties, current			$ 0	100
Altair Bellingham LLC [Member]
Related Party Transaction [Line Items]
Payment to acquire business		$ 700
FluiDyna GmbH [Member] | Other long-term assets [Member]
Related Party Transaction [Line Items]
Receivables from equity investment				$ 500
Founder Stockholders [Member]
Related Party Transaction [Line Items]
Purchase of noncontrolling interests	$ (29)
Founder Stockholders [Member] | Class A Common Stock [Member]
Related Party Transaction [Line Items]
Stock redeemed in shares | shares					546,776
Stock redeemed aggregate purchase price					$ 2,100
Founder Stockholders [Member] | Class B Common Stock [Member]
Related Party Transaction [Line Items]
Stock redeemed in shares | shares					113,388
Stock redeemed aggregate purchase price					$ 600
Number of installments | Installment					9

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Millions	Nov. 13, 2014	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2013
Loss Contingencies [Line Items]
Damages amount on MSC litigation	$ 0.4
Rent expense for operating leases		$ 11	$ 9.9	$ 8.5
Minimum [Member]
Loss Contingencies [Line Items]
Operating lease term		1 year
Software and Other [Member]
Loss Contingencies [Line Items]
Royalty fees		$ 9.7	$ 9.3	$ 7.9
Datawatch Corporation [Member] | Panopticon AB [Member] | Swedish Tax Authorities [Member]
Loss Contingencies [Line Items]
Tax assessment, penalties and interest amount related to acquisition					$ 6.7

Commitments and Contingencies_2

Commitments and Contingencies - Schedule of Future Minimum Annual Lease Payments under Noncancelable Operating Leases and Capital Leases (Detail) $ in Thousands	Dec. 31, 2018USD ($)
Capital Leases, Future Minimum Payments Due, Fiscal Year Maturity
Capital leases, 2019	$ 256
Capital leases, 2020	209
Capital leases, 2021	173
Capital leases, 2022	137
Capital leases, 2023	38
Capital leases, Thereafter	0
Total minimum lease payments	813
Less: current installments under capital lease obligations	256
Total long-term portion	557
Year Ending December 31,
Operating leases, 2019	10,661
Operating leases, 2020	8,306
Operating leases, 2021	5,673
Operating leases, 2022	3,573
Operating leases, 2023	1,819
Operating leases, Thereafter	3,147
Total minimum lease payments	$ 33,179

Segment Information - Additiona

Segment Information - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2018Segment
Segment Reporting [Abstract]
Number of reportable segments	2

Segment Information - Schedule

Segment Information - Schedule of Segment Reporting Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Revenue	$ 396,379	$ 333,333	$ 313,240
Adjusted EBITDA	50,180	22,517	30,830
Software [Member]
Segment Reporting Information [Line Items]
Revenue	341,306	280,214	259,588
Adjusted EBITDA	48,643	22,864	29,411
CES [Member]
Segment Reporting Information [Line Items]
Revenue	47,852	46,510	47,702
Adjusted EBITDA	5,155	4,966	5,425
All Other [Member]
Segment Reporting Information [Line Items]
Revenue	7,221	6,609	5,950
Adjusted EBITDA	$ (3,618)	$ (5,313)	$ (4,006)

Segment Information - Reconcili

Segment Information - Reconciliation of U.S. GAAP (Loss) Income Before Income Taxes to Adjusted EBITDA (Detail) - USD ($) $ in Thousands		3 Months Ended			12 Months Ended
		Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting [Abstract]
Adjusted EBITDA					$ 50,180	$ 22,517	$ 30,830
Stock-based compensation expense		$ (8,000)	$ (25,300)	$ (11,200)	(3,339)	(47,281)	(5,132)
Interest expense	[1]				(200)	(2,160)	(2,265)
Interest income and other	[2]				(4,883)	2,260	249
Depreciation and amortization					(14,734)	(11,747)	(9,980)
Income (loss) before income taxes	[1]				$ 27,024	$ (36,411)	$ 13,702
[1]	The year ended December 31, 2018 has been reported under ASC 606, and the years ended December 31, 2017 and 2016 have been reported under ASC 605 and have not been adjusted under the modified retrospective approach. See Note 3 – Revenue from contracts with customers for the effect of the adoption of ASC 606 on the Company’s consolidated financial statements.
[2]	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, c) impairment charges for royalty contracts and trade names resulting in $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 resulting in $2.0 million of income in each year.

Segment Information - Reconci_2

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
	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Gain on sale of building		$ 4.4
Impairment charge recognized in non-recurring adjustment for royalty contracts		2.8
Income recognized in non-recurring adjustment for change in estimated legal expenses	$ 2	2	$ 2
Datawatch Corporation [Member]
Segment Reporting Information [Line Items]
Nonrecurring costs from acquisition		$ 10.4

Segment Information - Summary o

Segment Information - Summary of Sales to External Customers and Long-Lived Assets by Geographical Areas (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue		$ 396,379	$ 333,333	$ 313,240
Long-lived assets	[1]	90,332	53,168
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue		186,026	142,679	139,079
Long-lived assets	[1]	63,266	38,729
Other American Countries [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue		8,604	6,404	6,032
Long-lived assets	[1]	11,447	116
Americas [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue		194,630	149,083	145,111
Long-lived assets	[1]	74,713	38,845
Germany [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue		45,664	43,751	39,470
Long-lived assets	[1]	4,305	2,802
France [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue		16,154	18,128	15,729
Long-lived assets	[1]	1,583	2,176
Other Europe, Middle East and Africa Countries [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue		42,846	40,050	34,909
Long-lived assets	[1]	4,729	4,534
Europe Middle East And Africa [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue		104,664	101,929	90,108
Long-lived assets	[1]	10,617	9,512
Japan [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue		35,478	33,686	33,198
Long-lived assets	[1]	2,045	2,237
Other Asia Pacific Countries [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue		61,607	48,635	44,823
Long-lived assets	[1]	2,957	2,574
Asia Pacific [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue		97,085	82,321	$ 78,021
Long-lived assets	[1]	$ 5,002	$ 4,811
[1]	Includes property and equipment, net and definite-lived intangible assets, net.

Supplemental Quarterly Financ_3

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, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017		Sep. 30, 2017		Jun. 30, 2017		Mar. 31, 2017		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Total revenue	[1]													$ 396,379	$ 333,333	$ 313,240
Gross profit	[1]													280,406	226,742	210,640
Operating income (loss)	[1]													24,644	(33,257)	15,447
Net income (loss)	[1]													$ 13,715	$ (99,407)	$ 10,163
Net income (loss) per share, basic	[1]													$ 0.20	$ (1.89)	$ 0.21
Net income (loss) per share, diluted	[1]													$ 0.18	$ (1.89)	$ 0.18
Prior to Adoption of ASC 606 [Member]
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Total revenue		$ 103,894	$ 93,871	$ 95,566	$ 91,731	$ 89,867	[2]	$ 84,938	[2]	$ 81,646	[2]	$ 76,882	[2]
Gross profit		73,623	66,667	66,110	62,689	63,250	[2]	58,636	[2]	54,728	[2]	50,128	[2]
Operating income (loss)		(2,424)	8,968	2,177	4,270	(3,181)	[2]	(20,928)	[2]	(7,158)	[2]	(1,990)	[2]
Net income (loss)	[2]					$ (60,347)		$ (29,626)		$ (7,246)		$ (2,188)
Net income (loss) per share, basic	[2]					$ (1.03)		$ (0.59)		$ (0.14)		$ (0.04)
Net income (loss) per share, diluted	[2]					$ (1.03)		$ (0.59)		$ (0.14)		$ (0.04)
ASC 606 [Member]
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Total revenue		103,011	86,751	93,360	113,257
Gross profit		72,740	59,547	63,903	84,216
Operating income (loss)		(3,557)	1,880	175	26,146
Net income (loss)		$ (10,823)	$ 934	$ (1,080)	$ 24,684
Net income (loss) per share, basic		$ (0.15)	$ 0.01	$ (0.02)	$ 0.39
Net income (loss) per share, diluted		$ (0.15)	$ 0.01	$ (0.02)	$ 0.34
ASC 606 [Member] | Prior to Adoption of ASC 606 [Member]
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Gross profit														$ 269,089
Operating income (loss)														12,991
Net income (loss)														$ 2,899
Net income (loss) per share, basic														$ 0.04
Net income (loss) per share, diluted														$ 0.04
[1]	The year ended December 31, 2018 has been reported under ASC 606, and the years ended December 31, 2017 and 2016 have been reported under ASC 605 and have not been adjusted under the modified retrospective approach. See Note 3 – Revenue from contracts with customers for the effect of the adoption of ASC 606 on the Company’s consolidated financial statements.
[2]	The three months ended March 31, 2017, June 30, 2017, September 30, 2017 and December 31, 2017 have been reported under ASC 605 and have not been adjusted under the modified retrospective approach. 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 Financ_4

Supplemental Quarterly Financial Information (Unaudited) - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended					12 Months Ended
	Sep. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Supplemental Quarterly Financial Information [Line Items]
Income recognized in non-recurring adjustment for change in estimated legal expenses		$ 2,000				$ 2,000	$ 2,000
Stock-based compensation expense			$ 8,000	$ 25,300	$ 11,200	3,339	47,281	$ 5,132
Increase in income tax expense			$ 56,600
Tax cuts and job act, valuation allowance						$ 16,725	47,429
Tax cuts and job act, increase tax expense							$ 15,400
Building [Member]
Supplemental Quarterly Financial Information [Line Items]
Gain on sale of property and equipment	$ 4,400