ANSYS (ANSS) 10-Q 8 Nov 18 2018 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2018	Oct. 31, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3
Trading Symbol	ANSS
Entity Registrant Name	ANSYS INC
Entity Central Index Key	1,013,462
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Common Stock, Shares Outstanding		83,560,018

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 729,180	$ 881,501
Short-term investments	211	286
Accounts receivable, less allowance for doubtful accounts of $8,100 and $6,800, respectively	235,547	124,659
Other receivables and current assets	162,629	263,820
Total current assets	1,127,567	1,270,266
Property and equipment, net	57,902	57,096
Goodwill	1,575,567	1,378,553
Other intangible assets, net	219,564	157,625
Other long-term assets	53,226	35,972
Deferred income taxes	22,285	42,111
Total assets	3,056,111	2,941,623
Current liabilities:
Accounts payable	6,767	6,042
Accrued bonuses and commissions	46,720	69,925
Accrued income taxes	5,911	5,760
Other accrued expenses and liabilities	83,169	86,335
Deferred revenue - current	272,872	440,491
Total current liabilities	415,439	608,553
Long-term liabilities:
Deferred income taxes	29,955	1,461
Other long-term liabilities	62,171	85,778
Total long-term liabilities	92,126	87,239
Commitments and contingencies
Stockholders' equity:
Preferred stock, $.01 par value; 2,000,000 shares authorized; zero shares issued or outstanding	0	0
Common stock, $.01 par value; 300,000,000 shares authorized; 93,236,023 shares issued	932	932
Additional paid-in capital	850,616	873,357
Retained earnings	2,766,259	2,316,916
Treasury stock, at cost: 9,213,790 and 9,044,498 shares, respectively	(1,008,370)	(907,530)
Accumulated other comprehensive loss	(60,891)	(37,844)
Total stockholders' equity	2,548,546	2,245,831
Total liabilities and stockholders' equity	$ 3,056,111	$ 2,941,623

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Allowance for doubtful accounts	$ 8,100	$ 6,800
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	2,000,000	2,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	300,000,000	300,000,000
Common stock, shares issued	93,236,023	93,236,023
Treasury stock, shares	9,213,790	9,044,498

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenue:
Total revenue	$ 289,418	$ 275,585	$ 878,204	$ 792,914
Cost of sales:
Amortization	5,530	9,004	23,403	26,892
Total cost of sales	36,308	35,983	115,796	109,352
Gross profit	253,110	239,602	762,408	683,562
Operating expenses:
Selling, general and administrative	97,576	80,015	280,443	230,483
Research and development	59,019	50,144	174,906	153,524
Amortization	3,491	3,260	10,421	9,506
Total operating expenses	160,086	133,419	465,770	393,513
Operating income	93,024	106,183	296,638	290,049
Interest income	3,213	1,910	7,674	4,827
Other expense, net	(974)	(168)	(2,289)	(1,512)
Income before income tax provision	95,263	107,925	302,023	293,364
Income tax provision	5,927	34,295	35,811	86,698
Net income	$ 89,336	$ 73,630	$ 266,212	$ 206,666
Earnings per share - basic:
Earnings per share	$ 1.06	$ 0.87	$ 3.17	$ 2.43
Weighted average shares	84,158	84,774	84,065	85,132
Earnings per share - diluted:
Earnings per share	$ 1.04	$ 0.85	$ 3.09	$ 2.38
Weighted average shares	86,043	86,588	86,060	86,902
Software licenses
Revenue:
Total revenue	$ 109,103	$ 156,580	$ 350,296	$ 448,368
Cost of sales:
Total cost of sales	4,291	7,395	12,301	24,197
Maintenance and service
Revenue:
Total revenue	180,315	119,005	527,908	344,546
Cost of sales:
Total cost of sales	$ 26,487	$ 19,584	$ 80,092	$ 58,263

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Net income	$ 89,336	$ 73,630	$ 266,212	$ 206,666
Other comprehensive (loss) income:
Foreign currency translation adjustments	(5,102)	4,149	(23,047)	18,225
Comprehensive income	$ 84,234	$ 77,779	$ 243,165	$ 224,891

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash flows from operating activities:
Net income	$ 266,212	$ 206,666
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	47,341	49,939
Deferred income tax benefit	(28,175)	(4,217)
Provision for bad debts	1,389	1,382
Stock-based compensation expense	58,887	39,408
Other	2,039	241
Changes in operating assets and liabilities:
Accounts receivable	32,356	17,899
Other receivables and current assets	23,207	60,754
Other long-term assets	2,458	4,495
Accounts payable, accrued expenses and current liabilities	(31,243)	(22,362)
Accrued income taxes	(2,581)	(221)
Deferred revenue	1,175	(35,502)
Other long-term liabilities	(19,562)	8,478
Net cash provided by operating activities	353,503	326,960
Cash flows from investing activities:
Acquisitions, net of cash acquired	(283,026)	(25,998)
Capital expenditures	(13,077)	(14,815)
Other investing activities	(5,510)	(20,810)
Net cash used in investing activities	(301,613)	(61,623)
Cash flows from financing activities:
Purchase of treasury stock	(192,787)	(223,291)
Restricted stock withholding taxes paid in lieu of issued shares	(26,955)	(10,075)
Proceeds from shares issued for stock-based compensation	37,398	47,992
Other financing activities	(4,939)	0
Net cash used in financing activities	(187,283)	(185,374)
Effect of exchange rate fluctuations on cash and cash equivalents	(16,928)	17,129
Net (decrease) increase in cash and cash equivalents	(152,321)	97,092
Cash and cash equivalents, beginning of period	881,501	822,479
Cash and cash equivalents, end of period	729,180	919,571
Supplemental disclosures of cash flow information:
Income taxes paid	$ 74,086	$ 84,760

Organization

Organization	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	Organization ANSYS, Inc. (hereafter the Company or ANSYS) develops and globally markets engineering simulation software and services widely used by engineers, designers, researchers and students across a broad spectrum of industries and academia, including aerospace and defense, automotive, electronics, semiconductors, energy, materials and chemical processing, turbomachinery, consumer products, healthcare, and sports. As defined by the accounting guidance for segment reporting, the Company operates as one segment. Given the integrated approach to the multi-discipline problem-solving needs of the Company's customers, a single sale of software may contain components from multiple product areas and include combined technologies. The Company also has a multi-year product and integration strategy that will result in new, combined products or changes to the historical product offerings. As a result, it is impracticable for the Company to provide accurate historical or current reporting among its various product lines.

Accounting Policies

Accounting Policies	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Accounting Policies	Accounting Policies Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared by ANSYS in accordance with accounting principles generally accepted in the United States for interim financial information for commercial and industrial companies and the instructions to the Quarterly Report on Form 10-Q and Rule 10-01 of Regulation S-X. Accordingly, the accompanying statements do not include all of the information and footnotes required by accounting principles generally accepted in the United States for complete financial statements. The accompanying condensed consolidated financial statements should be read in conjunction with the Company's audited consolidated financial statements (and notes thereto) included in the Company's Annual Report on Form 10-K for the year ended December 31, 2017 . The condensed consolidated December 31, 2017 balance sheet presented is derived from the audited December 31, 2017 balance sheet included in the most recent Annual Report on Form 10-K. In the opinion of management, all adjustments considered necessary for a fair presentation of the financial statements have been included, and all adjustments are of a normal and recurring nature. Certain items in the notes to the condensed consolidated financial statements of prior years have been reclassified to conform to the current year's presentation. These reclassifications had no effect on reported net income, comprehensive income, cash flows, total assets or total liabilities and stockholders' equity. Operating results for the three and nine months ended September 30, 2018 are not necessarily indicative of the results that may be expected for any future period. Changes in Accounting Policies The Company’s accounting policies are described in Note 2, “Accounting Policies,” in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017 . Summarized below is the accounting guidance adopted subsequent to December 31, 2017 . Revenue from contracts with customers: In May 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers (Topic 606) (ASU 2014-09). The Company adopted ASU 2014-09 and its related amendments (collectively known as ASC 606) effective January 1, 2018 using the modified retrospective approach. See Note 3 for the required disclosures related to the impact of adopting this standard and a discussion of the Company's updated policies related to revenue recognition. Income taxes: In October 2016, the FASB issued Accounting Standards Update No. 2016-16, Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory (ASU 2016-16). The Company adopted ASU 2016-16 effective January 1, 2018 using the modified retrospective approach. Previous guidance required the tax effects from intra-entity asset transfers to be deferred until the asset was sold to a third party or recovered through use. ASU 2016-16 eliminated this deferral for all intra-entity asset transfers other than inventory. The adoption of the standard did not have a material effect on the Company’s condensed consolidated financial statements. Business combinations: In January 2017, the FASB issued Accounting Standards Update No. 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business (ASU 2017-01). The Company prospectively adopted ASU 2017-01 effective January 1, 2018. This standard narrows the definition of a business. If substantially all the fair value of the gross assets acquired is concentrated in a single identifiable asset or group of similar identifiable assets, the acquiree is not a business. The standard also requires a business to include an input and a substantive process that significantly contributes to the ability to create outputs. This definition is expected to reduce the number of acquisitions accounted for as business combinations, which will impact the accounting treatment of certain items, including the accounting treatment of contingent consideration and transaction expenses. Accounting Guidance Issued and Not Yet Adopted Leases: In February 2016, the FASB issued Accounting Standards Update No. 2016-02, Leases (Topic 842) (ASU 2016-02). ASU 2016-02 requires virtually all leases, other than leases that meet the definition of a short-term lease or leases of intangible assets, to be recorded on the balance sheet with a right-of-use asset and a corresponding lease liability. Leases will be classified as either operating or finance leases based on certain criteria. This classification will determine the timing and presentation of expenses on the income statement, as well as the presentation of related cash flows. The standard is effective for annual periods beginning after December 15, 2018, including interim periods within that reporting period. A modified retrospective transition is required upon adoption. The Company plans to adopt ASU 2016-02 effective January 1, 2019 and continues to evaluate the effect that this update will have on its financial results upon adoption. The Company's preliminary assessment is that this update will materially increase the Company's assets and liabilities upon adoption. The Company has completed the inventory of its leases and policy elections, and expects that it will primarily have operating leases. The Company is currently implementing new processes and controls to meet the accounting and disclosure requirements under the new standard. Credit losses: In June 2016, the FASB issued Accounting Standards Update No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (ASU 2016-13). The current guidance requires the allowance for doubtful accounts to be estimated based on an incurred loss model, which considers past and current conditions. ASU 2016-13 requires companies to use an expected loss model that also considers reasonable and supportable forecasts of future conditions. ASU 2016-13 is effective for annual periods beginning after December 15, 2019, including interim periods within that reporting period. Early adoption is permitted for annual periods beginning after December 15, 2018, including interim periods within that reporting period. The standard requires a cumulative-effect adjustment to the balance sheet as of the beginning of the first reporting period in which the guidance is effective. The Company is currently evaluating the effect that this update will have on its financial results upon adoption. Implementation cost accounting for cloud computing arrangements: In August 2018, the FASB issued Accounting Standards Update No. 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 (ASU 2018-15). The standard aligns the accounting for costs incurred to implement a cloud computing arrangement (CCA) that is a service arrangement with the guidance on capitalizing costs associated with developing or obtaining internal-use software. Under ASU 2018-15, an entity would apply Subtopic 350-40 to determine which implementation costs related to a CCA that is a service contract should be capitalized. The standard does not change the accounting for the service component of a CCA. The associated cash flows will be reflected within operating activities. ASU 2018-15 is effective for annual periods beginning after December 15, 2019, including interim periods within that reporting period. Early adoption is permitted, including adoption in any interim period for which financial statements have not been issued. Entities can choose to adopt the new guidance (1) prospectively to eligible costs incurred on or after the date the guidance is first applied or (2) retrospectively. The Company is currently evaluating the effect that this update will have on its financial results upon adoption. Cash and Cash Equivalents Cash and cash equivalents consist primarily of highly liquid investments such as deposits held at major banks and money market funds. Cash equivalents are carried at cost, which approximates fair value. The Company’s cash and cash equivalent balances comprise the following: September 30, 2018 December 31, 2017 (in thousands, except percentages) Amount % of Total Amount % of Total Cash accounts $ 332,097 45.5 $ 568,587 64.5 Money market funds 397,083 54.5 312,914 35.5 Total $ 729,180 $ 881,501 The Company's money market fund balances are held in various funds of a single issuer.

Revenue from Contracts with Cus

Revenue from Contracts with Customers	9 Months Ended
	Sep. 30, 2018
Revenue from Contract with Customer [Abstract]
Revenue from Contracts with Customers	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 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, Revenue Recognition (ASC 605). The adoption of ASC 606 represents a change in accounting principle that will more closely align revenue recognition with the delivery of the Company’s software licenses, maintenance and 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. The Company recorded an increase to retained earnings of $242.4 million , or $183.1 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 time-based software lease licenses. Revenue Recognition Revenue is derived principally from the licensing of computer 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 perpetual licenses is classified as software license revenue. Software license revenue is recognized up front upon delivery of the licensed product and the utility that enables the customer to access authorization keys, provided that a signed contract has been received. Typically, the Company’s perpetual licenses are sold with post-contract support (PCS), which includes unspecified technical enhancements and customer support. 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. In addition to perpetual licenses, the Company sells time-based lease licenses. Lease licenses are sold only as a bundled arrangement that includes the rights to a term software license and PCS. Maximizing the use of observable inputs, the Company determined that 50% of the estimated standalone selling price of the lease license is attributable to the term license and 50% is attributable to the PCS. Consistent with the perpetual sales, the license component is classified as software license revenue and recognized as revenue up front at the commencement of the lease. 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. Revenue from training, support 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 independent 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, a license agreement signed by the end-user customer is received 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 condensed consolidated balance sheet as accounts receivable and accrued expenses. The collection and payment of these amounts are reported on a net basis in the condensed consolidated statements of income and do not impact reported revenues or expenses. The Company warrants to its customers that its software will perform substantially as specified in the Company's current user manuals. The Company has not experienced significant claims related to software warranties beyond the scope of maintenance support, which the Company is already obligated to provide. The warranty is not sold, and cannot be purchased, separately. The warranty does not provide any type of additional service to the customer or performance obligation for the Company. Significant Judgments 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, and if so, the allocation of the transaction price to each performance obligation. The Company uses the estimated standalone selling price method to allocate the transaction price for items that are not sold separately, particularly lease licenses sold with PCS. The estimated standalone selling price is determined using all information reasonably available to the Company, including market conditions and other observable inputs. The corresponding revenues are recognized as the related performance obligations are satisfied. The Company applies a practical expedient to expense sales commissions as incurred when the amortization period would have been one year or less. Sales commissions associated with the initial year of multi-year contracts are expensed as incurred due to their immateriality. Sales commissions associated with multi-year contracts beyond the initial year are subject to an employee service requirement and are expensed as incurred as they are not considered incremental costs to obtain a contract. The Company is required to adjust promised amounts of consideration for the effects of the time value of money if the timing of the payments provides the customer or the Company with a significant financing benefit. The Company considers various factors in assessing whether a financing component exists, including the duration of the contract, market interest rates and the timing of payments. The Company’s contracts do not include a significant financing component requiring adjustment to the transaction price. Impact of ASC 606 on Condensed Consolidated Financial Statement Line Items The following table compares the impacted assets and liabilities on the condensed consolidated balance sheet as of September 30, 2018 to the amounts had ASC 605 been in effect: September 30, 2018 (in thousands) As Reported (ASC 606) ASC 605 Change Accounts receivable, less allowance for doubtful accounts of $8,100 $ 235,547 $ 102,626 $ 132,921 Other receivables and current assets 162,629 255,654 (93,025 ) Other long-term assets 53,226 38,670 14,556 Deferred income tax assets 22,285 61,123 (38,838 ) Accrued income taxes 5,911 5,853 58 Other accrued expenses and liabilities 83,169 84,836 (1,667 ) Deferred revenue - current 272,872 434,129 (161,257 ) Deferred income tax liabilities 29,955 22,535 7,420 Other long-term liabilities 62,171 73,008 (10,837 ) Stockholders' equity $ 2,548,546 $ 2,366,649 $ 181,897 The Company recorded $244.1 million of deferred revenue to retained earnings upon the adoption of ASC 606 on January 1, 2018. The pattern of software lease license revenue recognition has changed under ASC 606. Software lease license revenue was recognized ratably over the term of the contract under the previous guidance; however, approximately 50% of the contract is recognized up front at the commencement of the lease under ASC 606. This change in the pattern of revenue recognition, coupled with the recording of deferred revenue to retained earnings at the adoption date, resulted in the changes to the condensed consolidated balance sheet line items as noted in the table above. The following table compares the impacted amounts on the condensed consolidated statements of income for the three and nine months ended September 30, 2018 to the amounts had ASC 605 been in effect: Three Months Ended September 30, 2018 Nine Months Ended September 30, 2018 (in thousands, except per share data) As Reported (ASC 606) ASC 605 Change As Reported (ASC 606) ASC 605 Change Revenue: Software licenses $ 109,103 $ 166,606 $ (57,503 ) $ 350,296 $ 482,656 $ (132,360 ) Maintenance and service 180,315 135,350 44,965 527,908 397,895 130,013 Cost of sales: Software licenses 4,291 8,488 (4,197 ) 12,301 25,078 (12,777 ) Maintenance and service 26,487 22,290 4,197 80,092 67,315 12,777 Income tax provision 5,927 7,685 (1,758 ) 35,811 36,089 (278 ) Earnings per share: Basic $ 1.06 $ 1.19 $ (0.13 ) $ 3.17 $ 3.19 $ (0.02 ) Diluted $ 1.04 $ 1.16 $ (0.12 ) $ 3.09 $ 3.12 $ (0.03 ) The impacts to reported software licenses revenue, and maintenance and service revenue, were primarily due to the PCS portion of lease license contracts now being allocated to maintenance and service revenue under ASC 606. Under the previous guidance, this revenue was reported as software licenses revenue. This decrease to software licenses revenue was partially offset by the upfront recognition of the license component of lease revenue, which would have been recognized ratably over the contract under prior guidance. Consistent with the change in revenue, there was a corresponding reclassification within cost of sales. Costs incurred related to the PCS portion of lease license contracts are reflected in cost of maintenance and service. Under the previous guidance, such costs were reflected within cost of software licenses. 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 income tax payments associated with deferred revenue and backlog credited to retained earnings and never recognized as revenue in the financial statements. The 2018 tax payments related to the adoption of ASC 606 are expected to be $12.0 million - $15.0 million . Disaggregation of Revenue The following tables summarize revenue: Three Months Ended September 30, (in thousands) 2018 2018 2017 Revenue: Lease licenses $ 43,202 $ 106,461 $ 93,956 Perpetual licenses 65,901 60,145 62,624 Software licenses 109,103 166,606 156,580 Maintenance 171,463 126,436 112,300 Service 8,852 8,914 6,705 Maintenance and service 180,315 135,350 119,005 Total revenue $ 289,418 $ 301,956 $ 275,585 The Company’s software licenses revenue is recognized up front, while maintenance and service revenue is generally recognized over the term of the contract. Under ASC 606, the Company derived 24.5% of its total revenue through the indirect sales channel for the three months ended September 30, 2018 . Under ASC 605, the Company derived 23.5% and 24.1% of its total revenue through the indirect sales channel for the three months ended September 30, 2018 and 2017, respectively. Nine Months Ended September 30, (in thousands) 2018 (ASC 606) 2018 (ASC 605) 2017 (ASC 605) Revenue: Lease licenses $ 148,795 $ 308,699 $ 279,855 Perpetual licenses 201,501 173,957 168,513 Software licenses 350,296 482,656 448,368 Maintenance 500,962 370,847 324,338 Service 26,946 27,048 20,208 Maintenance and service 527,908 397,895 344,546 Total revenue $ 878,204 $ 880,551 $ 792,914 Under ASC 606, the Company derived 23.9% of its total revenue through the indirect sales channel for the nine months ended September 30, 2018 . Under ASC 605, the Company derived 23.5% and 24.3% of its total revenue through the indirect sales channel for the nine months ended September 30, 2018 and 2017, respectively. Deferred Revenue Deferred revenue consists of billings made or payments received in advance of revenue recognition from software license and maintenance 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 time between invoicing and when payment is due is not significant. The changes in deferred revenue, inclusive of both current and long-term, are as follows: (in thousands) Nine Months Ended September 30, 2018 Beginning balance – January 1 $ 299,730 Acquired deferred revenue 2,470 Recognition of deferred revenue (878,204 ) Deferral of revenue 868,522 Currency translation (6,065 ) Ending balance – September 30 $ 286,453 Revenue allocated to remaining performance obligations represents contracted revenue that has not yet been recognized, which includes deferred revenue and backlog. The Company's backlog represents installment billings for periods beyond the current quarterly billing cycle and customer orders received but not processed. Revenue recognized during the nine months ended September 30, 2018 reflected above of $878.2 million included amounts in deferred revenue and backlog at the beginning of the period of $334.4 million . Total revenue allocated to remaining performance obligations was $544.7 million as of September 30, 2018 and will be recognized as revenue as follows: (in thousands) Next 12 months $ 412,113 Months 13-24 97,182 Months 25-36 26,976 Thereafter 8,444 Total revenue allocated to remaining performance obligations $ 544,715

Acquisition

Acquisition	9 Months Ended
	Sep. 30, 2018
Business Combinations [Abstract]
Acquisition	Acquisition On May 2, 2018, the Company completed the acquisition of 100% of the shares of OPTIS, a premier provider of software for scientific simulation of light, human vision and physics-based visualization, for a purchase price of $291.0 million , paid in cash. The acquisition will extend the Company's portfolio into the area of optical simulation to provide comprehensive sensor solutions, covering visible and infrared light, electromagnetics and acoustics for camera, radar and lidar. The acquisition met the definition of a business under ASU 2017-01. The operating results of OPTIS have been included in the Company's condensed consolidated financial statements since May 2, 2018, the date of acquisition. The assets and liabilities of OPTIS have been recorded based upon management's estimates of their fair market values as of the acquisition date. The following tables summarize the fair value of consideration transferred and the fair values of identified assets acquired and liabilities assumed at the acquisition date: Fair Value of Consideration Transferred: (in thousands) Cash $ 290,983 Recognized Amounts of Identifiable Assets Acquired and Liabilities Assumed: (in thousands) Cash $ 7,957 Accounts receivable and other tangible assets 16,026 Developed software and core technologies (9 – 10 year life) 47,593 Customer lists (12 year life) 41,303 Trade names (4 – 10 year life) 10,749 Accounts payable and other liabilities (13,396 ) Deferred revenue (2,470 ) Net deferred tax liabilities (21,576 ) Total identifiable net assets $ 86,186 Goodwill $ 204,797 The goodwill, which is not tax-deductible, is attributed to intangible assets that do not qualify for separate recognition, including the assembled workforce of the acquired business and the synergies expected to arise as a result of the acquisition of OPTIS. The fair values of the assets acquired and liabilities assumed are based on preliminary calculations. The estimates and assumptions for these items are subject to change as additional information about what was known and knowable at the acquisition date is obtained during the measurement period (up to one year from the acquisition date). During the period since the OPTIS acquisition date, the Company adjusted the fair values of the assets acquired and liabilities assumed, with the offset recorded as a $2.1 million increase to goodwill. These adjustments were based on refinements to assumptions used in the preliminary valuation of accounts receivable and other tangible assets, developed software and core technologies, accounts payable and other liabilities, and information about what was known and knowable as of the acquisition date in the calculation of the net deferred tax liabilities. In valuing deferred revenue on the OPTIS balance sheet as of the acquisition date, the Company applied the fair value provisions applicable to the accounting for business combinations. Acquired deferred revenue with a historical carrying value of $14.2 million under ASC 606, and $22.3 million under ASC 605, was ascribed a fair value of $2.5 million on the opening balance sheet. As a result, the Company's post-acquisition revenue will be less than the sum of what would have otherwise been reported by ANSYS and OPTIS absent the acquisition. Under ASC 606, the impacts on reported revenue for the three and nine months ended September 30, 2018 were $3.5 million and $6.2 million , respectively. The expected impacts on reported revenue are $2.5 million and $8.7 million for the quarter ending December 31, 2018 and for the year ending December 31, 2018 , respectively. Under ASC 605, the impacts on reported revenue for the three and nine months ended September 30, 2018 were $5.9 million and $10.4 million , respectively. The expected impacts on reported revenue are $4.1 million and $14.5 million for the quarter ending December 31, 2018 and for the year ending December 31, 2018 , respectively. Full pro forma results of operations have not been presented as the effects of the OPTIS business combination were not material to the Company's consolidated results of operations. The table presented below reflects the impact of OPTIS from the date of acquisition to September 30, 2018 . The operating loss is derived from the OPTIS legal structure and does not include integration costs borne directly by ANSYS, Inc. and its non-OPTIS subsidiaries as a result of the acquisition. Three Months Ended September 30, 2018 Nine Months Ended September 30, 2018 (in thousands) ASC 606 ASC 605 ASC 606 ASC 605 Revenue $ 6,021 $ 3,803 $ 9,187 $ 5,873 Operating loss $ (2,769 ) $ (4,987 ) $ (6,081 ) $ (9,395 )

Receivables and Other Current A

Receivables and Other Current Assets	9 Months Ended
	Sep. 30, 2018
Prepaid Expense and Other Assets, Current [Abstract]
Receivables and Other Current Assets	Receivables and Other Current Assets The Company's receivables and other current assets comprise the following balances: (in thousands) September 30, December 31, Accounts receivable, less allowance for doubtful accounts of $8,100 and $6,800, respectively $ 235,547 $ 124,659 Receivables related to unrecognized revenue $ 93,960 $ 215,155 Income taxes receivable, including overpayments and refunds 32,444 21,663 Prepaid expenses and other current assets 36,225 27,002 Total other receivables and current assets $ 162,629 $ 263,820 Receivables for unrecognized revenue represent the current portion of billings made for software maintenance that have not yet been recognized as revenue. Upon the adoption of ASC 606 on January 1, 2018, the opening balances of accounts receivable and receivables related to unrecognized revenue were $278.8 million and $136.4 million , respectively.

Earnings Per Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share Basic earnings per share (EPS) amounts are computed by dividing earnings by the weighted average number of common shares outstanding during the period. Diluted EPS amounts assume the issuance of common stock for all potentially dilutive equivalents outstanding. To the extent stock awards are anti-dilutive, they are excluded from the calculation of diluted EPS. The details of basic and diluted EPS are as follows: Three Months Ended Nine Months Ended (in thousands, except per share data) September 30, September 30, September 30, September 30, Net income $ 89,336 $ 73,630 $ 266,212 $ 206,666 Weighted average shares outstanding – basic 84,158 84,774 84,065 85,132 Dilutive effect of stock plans 1,885 1,814 1,995 1,770 Weighted average shares outstanding – diluted 86,043 86,588 86,060 86,902 Basic earnings per share $ 1.06 $ 0.87 $ 3.17 $ 2.43 Diluted earnings per share $ 1.04 $ 0.85 $ 3.09 $ 2.38 Anti-dilutive shares — 27 — 112

Goodwill and Intangible Assets

Goodwill and Intangible Assets	9 Months Ended
	Sep. 30, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	Goodwill and Intangible Assets The Company's intangible assets and estimated useful lives are classified as follows: September 30, 2018 December 31, 2017 (in thousands) Gross Carrying Amount Accumulated Amortization Gross Carrying Amount Accumulated Amortization Finite-lived intangible assets: Developed software and core technologies (3 – 11 years) $ 411,406 $ (311,938 ) $ 365,317 $ (297,645 ) Customer lists and contract backlog (5 – 15 years) 209,172 (113,881 ) 171,048 (104,522 ) Trade names (2 – 10 years) 137,402 (112,954 ) 127,200 (104,130 ) Total $ 757,980 $ (538,773 ) $ 663,565 $ (506,297 ) Indefinite-lived intangible asset: Trade name $ 357 $ 357 Amortization expense for the intangible assets reflected above was $9.0 million and $12.3 million for the three months ended September 30, 2018 and 2017 , respectively. Amortization expense for the intangible assets reflected above was $33.8 million and $36.4 million for the nine months ended September 30, 2018 and 2017 , respectively. As of September 30, 2018 , estimated future amortization expense for the intangible assets reflected above is as follows: (in thousands) Remainder of 2018 $ 7,142 2019 31,618 2020 32,823 2021 30,029 2022 26,342 2023 23,429 Thereafter 67,824 Total intangible assets subject to amortization 219,207 Indefinite-lived trade name 357 Other intangible assets, net $ 219,564 The changes in goodwill during the nine months ended September 30, 2018 and 2017 were as follows: (in thousands) 2018 2017 Beginning balance – January 1 $ 1,378,553 $ 1,337,215 Acquisitions and adjustments (1) 204,271 11,719 Currency translation (7,257 ) 4,510 Ending balance – September 30 $ 1,575,567 $ 1,353,444 (1) In accordance with the accounting for business combinations, the Company recorded adjustments to goodwill for the effect of changes in the provisional fair values of the assets acquired and liabilities assumed during the measurement period (up to one year from the acquisition date) as the Company obtained new information about facts and circumstances that existed as of the acquisition date that, if known, would have affected the measurement of the amounts recognized as of that date. During the first quarter of 2018 , the Company completed the annual impairment test for goodwill and the indefinite-lived intangible asset and determined that these assets had not been impaired as of the test date, January 1, 2018 . No other events or circumstances changed during the nine months ended September 30, 2018 that would indicate that the fair values of the Company's reporting unit and indefinite-lived intangible asset are below their carrying amounts.

Fair Value Measurement

Fair Value Measurement	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurement	Fair Value Measurement The valuation hierarchy for disclosure of assets and liabilities reported at fair value prioritizes the inputs for such valuations into three broad levels: • Level 1: quoted prices (unadjusted) in active markets for identical assets or liabilities; • Level 2: quoted prices for similar assets and liabilities in active markets or inputs that are observable for the asset or liability, either directly or indirectly through market corroboration, for substantially the full term of the financial instrument; or • Level 3: unobservable inputs based on the Company's own assumptions used to measure assets and liabilities at fair value. A financial asset's or liability's classification within the hierarchy is determined based on the lowest level input that is significant to the fair value measurement. The following tables provide the assets carried at fair value and measured on a recurring basis: Fair Value Measurements at Reporting Date Using: (in thousands) September 30, Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets Cash equivalents $ 397,083 $ 397,083 $ — $ — Short-term investments $ 211 $ — $ 211 $ — Deferred compensation plan investments $ 1,840 $ 1,840 $ — $ — Fair Value Measurements at Reporting Date Using: (in thousands) December 31, 2017 Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets Cash equivalents $ 312,914 $ 312,914 $ — $ — Short-term investments $ 286 $ — $ 286 $ — Deferred compensation plan investments $ 3,742 $ 3,742 $ — $ — The cash equivalents in the preceding tables represent money market funds. The short-term investments in the preceding tables represent deposits held by certain foreign subsidiaries of the Company. The deposits have fixed interest rates with maturity dates ranging from three months to one year . The deferred compensation plan investments in the preceding tables represent trading securities held in a rabbi trust for the benefit of the non-employee directors. These securities consist of mutual funds traded in an active market with quoted prices. As a result, the plan assets are classified as Level 1 in the fair value hierarchy. The plan assets are recorded within other long-term assets on the Company's condensed consolidated balance sheets. The carrying values of cash, accounts receivable, accounts payable, accrued expenses, other accrued liabilities and short-term obligations approximate their fair values because of their short-term nature.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Tax Cuts and Jobs Act On December 22, 2017, the U.S. government enacted comprehensive tax legislation commonly referred to as the Tax Cuts and Jobs Act (Tax Reform), making broad and complex changes to the U.S. tax code. The SEC staff issued Staff Accounting Bulletin (SAB) 118, which provides guidance on accounting for the tax effects of Tax Reform and allows for provisional adjustments recorded in the December 31, 2017 financial statements to be adjusted as calculations are completed during the measurement period. SAB 118 provides a measurement period that should not extend beyond one year from enactment for companies to complete the accounting under ASC 740, Income Taxes . As further discussed below, in accordance with SAB 118, the Company was able to complete final or provisional calculations for certain elements of Tax Reform, and the amounts and estimates are included in the financial statements and have been updated as additional information was gathered. For other elements, the Company was not yet able to make reasonable estimates, and therefore, those elements have not been recorded and are accounted for in accordance with ASC 740 on the basis of the tax laws in effect before Tax Reform. The Company’s accounting for the transition tax is incomplete. However, reasonable estimates of certain effects could be calculated, and a provisional adjustment of $16.0 million was recorded in the December 31, 2017 financial statements. To determine the amount of the transition tax, the Company must determine, in addition to other factors, the amount of post-1986 earnings and profits (E&P) of the relevant subsidiaries, as well as the amount of non-U.S. income taxes paid on such earnings. Based on revised E&P calculations updated during the measurement period, the Company recognized an additional measurement-period adjustment of $0.9 million to the transition tax obligation and a corresponding adjustment to tax expense, resulting in a total transition tax obligation of $16.9 million . The Company plans to elect to pay this liability over eight years; however, in accordance with IRS issued guidance, tax overpayments from the year ended December 31, 2017 are required to be applied to the transition tax obligation. Based on this guidance, $15.7 million of the obligation has been paid, with the remaining $1.2 million recorded in other long-term liabilities at September 30, 2018. The Company will continue to gather additional information to more precisely compute the final amount as further adjustments to E&P are determined. The Company expects to complete the accounting within the prescribed measurement period. The Company’s accounting for the indefinite reinvestment assertion is incomplete. However, a reasonable estimate of book and tax basis was calculated, and the Company made a provisional assertion. In general, it is the practice and intention of the Company to repatriate previously taxed earnings and to reinvest all other earnings of its non-U.S. subsidiaries. As part of Tax Reform, the Company incurred U.S. tax on substantially all of the earnings of its non-U.S. subsidiaries as part of the transition tax. This tax increased the Company’s previously taxed earnings and allows for the repatriation of the majority of its foreign earnings without any residual U.S. federal tax. The Company does not believe that there is an excess of the financial reporting basis over the tax basis of investments in foreign subsidiaries. Accordingly, any repatriation in excess of previously taxed earnings will be a non-taxable return of basis. This assertion is subject to change as additional information is gathered to precisely compute the book and tax bases of the Company’s non-U.S. subsidiaries. During the quarter ended June 30, 2018, the Company repatriated $144.3 million of foreign cash. The Company has not made any measurement-period adjustments related to its indefinite reinvestment assertion during the nine months ended September 30, 2018. However, the Company will continue to gather additional information and expects to complete the accounting within the measurement period. The Company’s accounting for the global intangible low-taxed income tax (GILTI) is incomplete. Due to the complexity of the new GILTI tax rules, the Company is continuing to evaluate this provision of Tax Reform and its application under ASC 740. Under U.S. GAAP, the Company is allowed to make an accounting policy choice of either (1) treating taxes due on future U.S. inclusions in taxable income related to GILTI as a current-period expense when incurred (the period cost method) or (2) factoring such amounts into the Company’s measurement of its deferred taxes (the deferred method). The Company’s selection of an accounting policy with respect to the new GILTI tax rules will depend, in part, on analyzing global income to determine whether future U.S. inclusions in taxable income related to GILTI are expected and, if so, the anticipated impact. Whether the Company expects to have future U.S. inclusions in taxable income related to GILTI depends not only on the current structure and estimated future results of global operations, but also on the Company’s intent and ability to modify the structure and/or the business. The Company has not made the accounting policy decision regarding whether to record deferred taxes on GILTI or expense taxes as incurred on GILTI. The current GILTI impact, which was immaterial for the three and nine months ended September 30, 2018, was recorded in the financial statements. The Company expects to complete the accounting for GILTI within the prescribed measurement period. Other Income Tax Matters The Company has $30.2 million of unrecognized tax benefits, including estimated interest and penalties, that have been recorded in other long-term liabilities in accordance with income tax accounting guidance and for which the Company is uncertain as to if or when such amounts may be settled.

Geographic Information

Geographic Information	9 Months Ended
	Sep. 30, 2018
Segments, Geographical Areas [Abstract]
Geographic Information	Geographic Information Revenue to external customers is attributed to individual countries based upon the location of the customer. Revenue by geographic area is as follows: Three Months Ended September 30, (in thousands) 2018 2018 2017 United States $ 106,229 $ 121,131 $ 105,480 Japan 36,309 33,331 30,779 Germany 27,831 30,728 28,395 China 14,568 14,703 14,043 France 14,035 15,116 13,438 South Korea 12,943 14,068 15,292 Other Europe, Middle East and Africa (EMEA) 45,602 43,066 40,887 Other international 31,901 29,813 27,271 Total revenue $ 289,418 $ 301,956 $ 275,585 Nine Months Ended September 30, (in thousands) 2018 2018 2017 United States $ 327,784 $ 345,886 $ 305,661 Japan 109,050 101,789 94,612 Germany 97,262 92,262 79,160 South Korea 45,468 46,305 45,633 France 44,638 45,511 37,997 China 38,616 37,870 35,429 Other EMEA 136,719 132,482 116,844 Other international 78,667 78,446 77,578 Total revenue $ 878,204 $ 880,551 $ 792,914 Property and equipment by geographic area is as follows: (in thousands) September 30, December 31, United States $ 44,117 $ 45,498 India 3,708 3,704 EMEA 6,326 5,114 Other international 3,751 2,780 Total property and equipment, net $ 57,902 $ 57,096

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Sep. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	Stock-Based Compensation Total stock-based compensation expense and its net impact on basic and diluted earnings per share are as follows: Three Months Ended Nine Months Ended (in thousands, except per share data) September 30, September 30, September 30, September 30, Cost of sales: Software licenses $ — $ 140 $ — $ 711 Maintenance and service 1,438 739 3,880 1,894 Operating expenses: Selling, general and administrative 13,484 8,782 33,288 23,310 Research and development 8,061 5,112 21,719 13,493 Stock-based compensation expense before taxes 22,983 14,773 58,887 39,408 Related income tax benefits (8,611 ) (6,080 ) (30,311 ) (23,980 ) Stock-based compensation expense, net of taxes $ 14,372 $ 8,693 $ 28,576 $ 15,428 Net impact on earnings per share: Basic earnings per share $ (0.17 ) $ (0.10 ) $ (0.34 ) $ (0.18 ) Diluted earnings per share $ (0.17 ) $ (0.10 ) $ (0.33 ) $ (0.18 )

Stock Repurchase Program

Stock Repurchase Program	9 Months Ended
	Sep. 30, 2018
Class of Stock Disclosures [Abstract]
Stock Repurchase Program	Stock Repurchase Program Under the Company's stock repurchase program, the Company repurchased shares as follows: Nine Months Ended (in thousands, except per share data) September 30, September 30, Number of shares repurchased 1,174 2,000 Average price paid per share $ 164.14 $ 111.65 Total cost $ 192,787 $ 223,291 In February 2018, the Company's Board of Directors increased the number of shares authorized for repurchase to a total of 5.0 million shares under the stock repurchase program. As of September 30, 2018 , 4.3 million shares remained available for repurchase under the program.

Restructuring

Restructuring	9 Months Ended
	Sep. 30, 2018
Restructuring and Related Activities [Abstract]
Restructuring	Restructuring During the fourth quarter of 2016, the Company initiated workforce realignment activities to reallocate resources to align with the Company's future strategic plans. The Company completed the workforce realignment activities as of September 30, 2017. The Company incurred related restructuring charges as follows: (in thousands) Gross Net of Tax Q4 2016 $ 3,419 $ 2,355 Q1 2017 9,273 6,176 Q2 2017 2,000 1,435 Q3 2017 466 331 Total restructuring charges $ 15,158 $ 10,297 The restructuring charges are included in the presentation of cost of software licenses; cost of maintenance and service; research and development expense; and selling, general and administrative expense. The gross charges were fully paid as of March 31, 2018.

Contingencies and Commitments

Contingencies and Commitments	9 Months Ended
	Sep. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Contingencies and Commitments	Contingencies and Commitments The Company is subject to various investigations, claims and legal proceedings that arise in the ordinary course of business, including commercial disputes, labor and employment matters, tax audits, alleged infringement of intellectual property rights and other matters. In the opinion of the Company, the resolution of pending matters is not expected to have a material adverse effect on the Company's consolidated results of operations, cash flows or financial position. However, each of these matters is subject to various uncertainties and it is possible that an unfavorable resolution of one or more of these proceedings could materially affect the Company's results of operations, cash flows or financial position. An Indian subsidiary of the Company has several service tax audits pending that have resulted in formal inquiries being received on transactions through mid-2012. The Company could incur tax charges and related liabilities of approximately $6.8 million . The service tax issues raised in the Company’s notices and inquiries are very similar to the case, M/s Microsoft Corporation (I) (P) Ltd. Vs. Commissioner of Service Tax, New Delhi, wherein the Delhi Customs, Excise and Service Tax Appellate Tribunal (CESTAT) passed a favorable ruling to Microsoft. The Microsoft case ruling was subsequently challenged in the Supreme Court by the Indian tax authority. The Company can provide no assurances on the impact that the present Microsoft case’s decision will have on the Company’s cases. The Company is uncertain as to when these service tax matters will be concluded. The Company sells software licenses and services to its customers under proprietary software license agreements. Each license agreement contains the relevant terms of the contractual arrangement with the customer, and generally includes certain provisions for indemnifying the customer against losses, expenses and liabilities from damages that are incurred by or awarded against the customer in the event the Company's software or services are found to infringe upon a patent, copyright or other proprietary right of a third party. To date, the Company has not had to reimburse any of its customers for any losses related to these indemnification provisions and no material claims asserted under these indemnification provisions are outstanding as of September 30, 2018 . For several reasons, including the lack of prior material indemnification claims, the Company cannot determine the maximum amount of potential future payments, if any, related to such indemnification provisions.

Accounting Policies (Policies)

Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared by ANSYS in accordance with accounting principles generally accepted in the United States for interim financial information for commercial and industrial companies and the instructions to the Quarterly Report on Form 10-Q and Rule 10-01 of Regulation S-X. Accordingly, the accompanying statements do not include all of the information and footnotes required by accounting principles generally accepted in the United States for complete financial statements. The accompanying condensed consolidated financial statements should be read in conjunction with the Company's audited consolidated financial statements (and notes thereto) included in the Company's Annual Report on Form 10-K for the year ended December 31, 2017 . The condensed consolidated December 31, 2017 balance sheet presented is derived from the audited December 31, 2017 balance sheet included in the most recent Annual Report on Form 10-K. In the opinion of management, all adjustments considered necessary for a fair presentation of the financial statements have been included, and all adjustments are of a normal and recurring nature. Certain items in the notes to the condensed consolidated financial statements of prior years have been reclassified to conform to the current year's presentation. These reclassifications had no effect on reported net income, comprehensive income, cash flows, total assets or total liabilities and stockholders' equity. Operating results for the three and nine months ended September 30, 2018 are not necessarily indicative of the results that may be expected for any future period.
Changes in Accounting Policies	Changes in Accounting Policies The Company’s accounting policies are described in Note 2, “Accounting Policies,” in the Company’s Annual Report on Form 10-K for the year ended December 31, 2017 . Summarized below is the accounting guidance adopted subsequent to December 31, 2017 . Revenue from contracts with customers: In May 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers (Topic 606) (ASU 2014-09). The Company adopted ASU 2014-09 and its related amendments (collectively known as ASC 606) effective January 1, 2018 using the modified retrospective approach. See Note 3 for the required disclosures related to the impact of adopting this standard and a discussion of the Company's updated policies related to revenue recognition. Income taxes: In October 2016, the FASB issued Accounting Standards Update No. 2016-16, Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory (ASU 2016-16). The Company adopted ASU 2016-16 effective January 1, 2018 using the modified retrospective approach. Previous guidance required the tax effects from intra-entity asset transfers to be deferred until the asset was sold to a third party or recovered through use. ASU 2016-16 eliminated this deferral for all intra-entity asset transfers other than inventory. The adoption of the standard did not have a material effect on the Company’s condensed consolidated financial statements. Business combinations: In January 2017, the FASB issued Accounting Standards Update No. 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business (ASU 2017-01). The Company prospectively adopted ASU 2017-01 effective January 1, 2018. This standard narrows the definition of a business. If substantially all the fair value of the gross assets acquired is concentrated in a single identifiable asset or group of similar identifiable assets, the acquiree is not a business. The standard also requires a business to include an input and a substantive process that significantly contributes to the ability to create outputs. This definition is expected to reduce the number of acquisitions accounted for as business combinations, which will impact the accounting treatment of certain items, including the accounting treatment of contingent consideration and transaction expenses.
Accounting Guidance Issued and Not Yet Adopted	Accounting Guidance Issued and Not Yet Adopted Leases: In February 2016, the FASB issued Accounting Standards Update No. 2016-02, Leases (Topic 842) (ASU 2016-02). ASU 2016-02 requires virtually all leases, other than leases that meet the definition of a short-term lease or leases of intangible assets, to be recorded on the balance sheet with a right-of-use asset and a corresponding lease liability. Leases will be classified as either operating or finance leases based on certain criteria. This classification will determine the timing and presentation of expenses on the income statement, as well as the presentation of related cash flows. The standard is effective for annual periods beginning after December 15, 2018, including interim periods within that reporting period. A modified retrospective transition is required upon adoption. The Company plans to adopt ASU 2016-02 effective January 1, 2019 and continues to evaluate the effect that this update will have on its financial results upon adoption. The Company's preliminary assessment is that this update will materially increase the Company's assets and liabilities upon adoption. The Company has completed the inventory of its leases and policy elections, and expects that it will primarily have operating leases. The Company is currently implementing new processes and controls to meet the accounting and disclosure requirements under the new standard. Credit losses: In June 2016, the FASB issued Accounting Standards Update No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (ASU 2016-13). The current guidance requires the allowance for doubtful accounts to be estimated based on an incurred loss model, which considers past and current conditions. ASU 2016-13 requires companies to use an expected loss model that also considers reasonable and supportable forecasts of future conditions. ASU 2016-13 is effective for annual periods beginning after December 15, 2019, including interim periods within that reporting period. Early adoption is permitted for annual periods beginning after December 15, 2018, including interim periods within that reporting period. The standard requires a cumulative-effect adjustment to the balance sheet as of the beginning of the first reporting period in which the guidance is effective. The Company is currently evaluating the effect that this update will have on its financial results upon adoption. Implementation cost accounting for cloud computing arrangements: In August 2018, the FASB issued Accounting Standards Update No. 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 (ASU 2018-15). The standard aligns the accounting for costs incurred to implement a cloud computing arrangement (CCA) that is a service arrangement with the guidance on capitalizing costs associated with developing or obtaining internal-use software. Under ASU 2018-15, an entity would apply Subtopic 350-40 to determine which implementation costs related to a CCA that is a service contract should be capitalized. The standard does not change the accounting for the service component of a CCA. The associated cash flows will be reflected within operating activities. ASU 2018-15 is effective for annual periods beginning after December 15, 2019, including interim periods within that reporting period. Early adoption is permitted, including adoption in any interim period for which financial statements have not been issued. Entities can choose to adopt the new guidance (1) prospectively to eligible costs incurred on or after the date the guidance is first applied or (2) retrospectively. The Company is currently evaluating the effect that this update will have on its financial results upon adoption.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash and cash equivalents consist primarily of highly liquid investments such as deposits held at major banks and money market funds. Cash equivalents are carried at cost, which approximates fair value. The Company’s cash and cash equivalent balances comprise the following: September 30, 2018 December 31, 2017 (in thousands, except percentages) Amount % of Total Amount % of Total Cash accounts $ 332,097 45.5 $ 568,587 64.5 Money market funds 397,083 54.5 312,914 35.5 Total $ 729,180 $ 881,501 The Company's money market fund balances are held in various funds of a single issuer.

Accounting Policies (Tables)

Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Cash and Cash Equivalents	The Company’s cash and cash equivalent balances comprise the following: September 30, 2018 December 31, 2017 (in thousands, except percentages) Amount % of Total Amount % of Total Cash accounts $ 332,097 45.5 $ 568,587 64.5 Money market funds 397,083 54.5 312,914 35.5 Total $ 729,180 $ 881,501

Revenue from Contracts with C_2

Revenue from Contracts with Customers (Tables)	9 Months Ended
	Sep. 30, 2018
Revenue from Contract with Customer [Abstract]
Impact of ASC 606 on Condensed Consolidated Financial Statement Line Items	The following table compares the impacted assets and liabilities on the condensed consolidated balance sheet as of September 30, 2018 to the amounts had ASC 605 been in effect: September 30, 2018 (in thousands) As Reported (ASC 606) ASC 605 Change Accounts receivable, less allowance for doubtful accounts of $8,100 $ 235,547 $ 102,626 $ 132,921 Other receivables and current assets 162,629 255,654 (93,025 ) Other long-term assets 53,226 38,670 14,556 Deferred income tax assets 22,285 61,123 (38,838 ) Accrued income taxes 5,911 5,853 58 Other accrued expenses and liabilities 83,169 84,836 (1,667 ) Deferred revenue - current 272,872 434,129 (161,257 ) Deferred income tax liabilities 29,955 22,535 7,420 Other long-term liabilities 62,171 73,008 (10,837 ) Stockholders' equity $ 2,548,546 $ 2,366,649 $ 181,897 The Company recorded $244.1 million of deferred revenue to retained earnings upon the adoption of ASC 606 on January 1, 2018. The pattern of software lease license revenue recognition has changed under ASC 606. Software lease license revenue was recognized ratably over the term of the contract under the previous guidance; however, approximately 50% of the contract is recognized up front at the commencement of the lease under ASC 606. This change in the pattern of revenue recognition, coupled with the recording of deferred revenue to retained earnings at the adoption date, resulted in the changes to the condensed consolidated balance sheet line items as noted in the table above. The following table compares the impacted amounts on the condensed consolidated statements of income for the three and nine months ended September 30, 2018 to the amounts had ASC 605 been in effect: Three Months Ended September 30, 2018 Nine Months Ended September 30, 2018 (in thousands, except per share data) As Reported (ASC 606) ASC 605 Change As Reported (ASC 606) ASC 605 Change Revenue: Software licenses $ 109,103 $ 166,606 $ (57,503 ) $ 350,296 $ 482,656 $ (132,360 ) Maintenance and service 180,315 135,350 44,965 527,908 397,895 130,013 Cost of sales: Software licenses 4,291 8,488 (4,197 ) 12,301 25,078 (12,777 ) Maintenance and service 26,487 22,290 4,197 80,092 67,315 12,777 Income tax provision 5,927 7,685 (1,758 ) 35,811 36,089 (278 ) Earnings per share: Basic $ 1.06 $ 1.19 $ (0.13 ) $ 3.17 $ 3.19 $ (0.02 ) Diluted $ 1.04 $ 1.16 $ (0.12 ) $ 3.09 $ 3.12 $ (0.03 ) The impacts to reported software licenses revenue, and maintenance and service revenue, were primarily due to the PCS portion of lease license contracts now being allocated to maintenance and service revenue under ASC 606. Under the previous guidance, this revenue was reported as software licenses revenue. This decrease to software licenses revenue was partially offset by the upfront recognition of the license component of lease revenue, which would have been recognized ratably over the contract under prior guidance. Consistent with the change in revenue, there was a corresponding reclassification within cost of sales. Costs incurred related to the PCS portion of lease license contracts are reflected in cost of maintenance and service. Under the previous guidance, such costs were reflected within cost of software licenses.
Disaggregation of Revenue	The following tables summarize revenue: Three Months Ended September 30, (in thousands) 2018 2018 2017 Revenue: Lease licenses $ 43,202 $ 106,461 $ 93,956 Perpetual licenses 65,901 60,145 62,624 Software licenses 109,103 166,606 156,580 Maintenance 171,463 126,436 112,300 Service 8,852 8,914 6,705 Maintenance and service 180,315 135,350 119,005 Total revenue $ 289,418 $ 301,956 $ 275,585 The Company’s software licenses revenue is recognized up front, while maintenance and service revenue is generally recognized over the term of the contract. Under ASC 606, the Company derived 24.5% of its total revenue through the indirect sales channel for the three months ended September 30, 2018 . Under ASC 605, the Company derived 23.5% and 24.1% of its total revenue through the indirect sales channel for the three months ended September 30, 2018 and 2017, respectively. Nine Months Ended September 30, (in thousands) 2018 (ASC 606) 2018 (ASC 605) 2017 (ASC 605) Revenue: Lease licenses $ 148,795 $ 308,699 $ 279,855 Perpetual licenses 201,501 173,957 168,513 Software licenses 350,296 482,656 448,368 Maintenance 500,962 370,847 324,338 Service 26,946 27,048 20,208 Maintenance and service 527,908 397,895 344,546 Total revenue $ 878,204 $ 880,551 $ 792,914 Under ASC 606, the Company derived 23.9% of its total revenue through the indirect sales channel for the nine months ended September 30, 2018 . Under ASC 605, the Company derived 23.5% and 24.3% of its total revenue through the indirect sales channel for the nine months ended September 30, 2018 and 2017, respectively.
Changes in Deferred Revenue	The changes in deferred revenue, inclusive of both current and long-term, are as follows: (in thousands) Nine Months Ended September 30, 2018 Beginning balance – January 1 $ 299,730 Acquired deferred revenue 2,470 Recognition of deferred revenue (878,204 ) Deferral of revenue 868,522 Currency translation (6,065 ) Ending balance – September 30 $ 286,453
Remaining Performance Obligations, Expected Timing of Satisfaction	Total revenue allocated to remaining performance obligations was $544.7 million as of September 30, 2018 and will be recognized as revenue as follows: (in thousands) Next 12 months $ 412,113 Months 13-24 97,182 Months 25-36 26,976 Thereafter 8,444 Total revenue allocated to remaining performance obligations $ 544,715

Acquisition (Tables)

Acquisition (Tables)	9 Months Ended
	Sep. 30, 2018
Schedule of Consideration Transferred	Fair Value of Consideration Transferred: (in thousands) Cash $ 290,983
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	Recognized Amounts of Identifiable Assets Acquired and Liabilities Assumed: (in thousands) Cash $ 7,957 Accounts receivable and other tangible assets 16,026 Developed software and core technologies (9 – 10 year life) 47,593 Customer lists (12 year life) 41,303 Trade names (4 – 10 year life) 10,749 Accounts payable and other liabilities (13,396 ) Deferred revenue (2,470 ) Net deferred tax liabilities (21,576 ) Total identifiable net assets $ 86,186 Goodwill $ 204,797
Business Acquisition, Pro Forma Information	The table presented below reflects the impact of OPTIS from the date of acquisition to September 30, 2018 . The operating loss is derived from the OPTIS legal structure and does not include integration costs borne directly by ANSYS, Inc. and its non-OPTIS subsidiaries as a result of the acquisition. Three Months Ended September 30, 2018 Nine Months Ended September 30, 2018 (in thousands) ASC 606 ASC 605 ASC 606 ASC 605 Revenue $ 6,021 $ 3,803 $ 9,187 $ 5,873 Operating loss $ (2,769 ) $ (4,987 ) $ (6,081 ) $ (9,395 )

Receivables and Other Current_2

Receivables and Other Current Assets (Tables)	9 Months Ended
	Sep. 30, 2018
Prepaid Expense and Other Assets, Current [Abstract]
Schedule of Receivables and Other Current Assets	The Company's receivables and other current assets comprise the following balances: (in thousands) September 30, December 31, Accounts receivable, less allowance for doubtful accounts of $8,100 and $6,800, respectively $ 235,547 $ 124,659 Receivables related to unrecognized revenue $ 93,960 $ 215,155 Income taxes receivable, including overpayments and refunds 32,444 21,663 Prepaid expenses and other current assets 36,225 27,002 Total other receivables and current assets $ 162,629 $ 263,820

Earnings Per Share (Tables)

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2018
Earnings Per Share [Abstract]
Details of Basic and Diluted EPS	The details of basic and diluted EPS are as follows: Three Months Ended Nine Months Ended (in thousands, except per share data) September 30, September 30, September 30, September 30, Net income $ 89,336 $ 73,630 $ 266,212 $ 206,666 Weighted average shares outstanding – basic 84,158 84,774 84,065 85,132 Dilutive effect of stock plans 1,885 1,814 1,995 1,770 Weighted average shares outstanding – diluted 86,043 86,588 86,060 86,902 Basic earnings per share $ 1.06 $ 0.87 $ 3.17 $ 2.43 Diluted earnings per share $ 1.04 $ 0.85 $ 3.09 $ 2.38 Anti-dilutive shares — 27 — 112

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets and Estimated Useful Lives	The Company's intangible assets and estimated useful lives are classified as follows: September 30, 2018 December 31, 2017 (in thousands) Gross Carrying Amount Accumulated Amortization Gross Carrying Amount Accumulated Amortization Finite-lived intangible assets: Developed software and core technologies (3 – 11 years) $ 411,406 $ (311,938 ) $ 365,317 $ (297,645 ) Customer lists and contract backlog (5 – 15 years) 209,172 (113,881 ) 171,048 (104,522 ) Trade names (2 – 10 years) 137,402 (112,954 ) 127,200 (104,130 ) Total $ 757,980 $ (538,773 ) $ 663,565 $ (506,297 ) Indefinite-lived intangible asset: Trade name $ 357 $ 357
Estimated Future Amortization Expense for Intangible Assets	As of September 30, 2018 , estimated future amortization expense for the intangible assets reflected above is as follows: (in thousands) Remainder of 2018 $ 7,142 2019 31,618 2020 32,823 2021 30,029 2022 26,342 2023 23,429 Thereafter 67,824 Total intangible assets subject to amortization 219,207 Indefinite-lived trade name 357 Other intangible assets, net $ 219,564
Changes in Goodwill	The changes in goodwill during the nine months ended September 30, 2018 and 2017 were as follows: (in thousands) 2018 2017 Beginning balance – January 1 $ 1,378,553 $ 1,337,215 Acquisitions and adjustments (1) 204,271 11,719 Currency translation (7,257 ) 4,510 Ending balance – September 30 $ 1,575,567 $ 1,353,444 (1) In accordance with the accounting for business combinations, the Company recorded adjustments to goodwill for the effect of changes in the provisional fair values of the assets acquired and liabilities assumed during the measurement period (up to one year from the acquisition date) as the Company obtained new information about facts and circumstances that existed as of the acquisition date that, if known, would have affected the measurement of the amounts recognized as of that date.

Fair Value Measurement (Tables)

Fair Value Measurement (Tables)	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value of Assets and Liabilities Measured on Recurring Basis	The following tables provide the assets carried at fair value and measured on a recurring basis: Fair Value Measurements at Reporting Date Using: (in thousands) September 30, Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets Cash equivalents $ 397,083 $ 397,083 $ — $ — Short-term investments $ 211 $ — $ 211 $ — Deferred compensation plan investments $ 1,840 $ 1,840 $ — $ — Fair Value Measurements at Reporting Date Using: (in thousands) December 31, 2017 Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets Cash equivalents $ 312,914 $ 312,914 $ — $ — Short-term investments $ 286 $ — $ 286 $ — Deferred compensation plan investments $ 3,742 $ 3,742 $ — $ —

Geographic Information (Tables)

Geographic Information (Tables)	9 Months Ended
	Sep. 30, 2018
Segments, Geographical Areas [Abstract]
Revenue by Geographic Area	Revenue by geographic area is as follows: Three Months Ended September 30, (in thousands) 2018 2018 2017 United States $ 106,229 $ 121,131 $ 105,480 Japan 36,309 33,331 30,779 Germany 27,831 30,728 28,395 China 14,568 14,703 14,043 France 14,035 15,116 13,438 South Korea 12,943 14,068 15,292 Other Europe, Middle East and Africa (EMEA) 45,602 43,066 40,887 Other international 31,901 29,813 27,271 Total revenue $ 289,418 $ 301,956 $ 275,585 Nine Months Ended September 30, (in thousands) 2018 2018 2017 United States $ 327,784 $ 345,886 $ 305,661 Japan 109,050 101,789 94,612 Germany 97,262 92,262 79,160 South Korea 45,468 46,305 45,633 France 44,638 45,511 37,997 China 38,616 37,870 35,429 Other EMEA 136,719 132,482 116,844 Other international 78,667 78,446 77,578 Total revenue $ 878,204 $ 880,551 $ 792,914
Property and Equipment by Geographic Area	Property and equipment by geographic area is as follows: (in thousands) September 30, December 31, United States $ 44,117 $ 45,498 India 3,708 3,704 EMEA 6,326 5,114 Other international 3,751 2,780 Total property and equipment, net $ 57,902 $ 57,096

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation Expense and Its Net Impact on Basic and Diluted Earnings Per Share	Total stock-based compensation expense and its net impact on basic and diluted earnings per share are as follows: Three Months Ended Nine Months Ended (in thousands, except per share data) September 30, September 30, September 30, September 30, Cost of sales: Software licenses $ — $ 140 $ — $ 711 Maintenance and service 1,438 739 3,880 1,894 Operating expenses: Selling, general and administrative 13,484 8,782 33,288 23,310 Research and development 8,061 5,112 21,719 13,493 Stock-based compensation expense before taxes 22,983 14,773 58,887 39,408 Related income tax benefits (8,611 ) (6,080 ) (30,311 ) (23,980 ) Stock-based compensation expense, net of taxes $ 14,372 $ 8,693 $ 28,576 $ 15,428 Net impact on earnings per share: Basic earnings per share $ (0.17 ) $ (0.10 ) $ (0.34 ) $ (0.18 ) Diluted earnings per share $ (0.17 ) $ (0.10 ) $ (0.33 ) $ (0.18 )

Stock Repurchase Program (Table

Stock Repurchase Program (Tables)	9 Months Ended
	Sep. 30, 2018
Class of Stock Disclosures [Abstract]
Stock Repurchase Program	Under the Company's stock repurchase program, the Company repurchased shares as follows: Nine Months Ended (in thousands, except per share data) September 30, September 30, Number of shares repurchased 1,174 2,000 Average price paid per share $ 164.14 $ 111.65 Total cost $ 192,787 $ 223,291

Restructuring (Tables)

Restructuring (Tables)	9 Months Ended
	Sep. 30, 2018
Restructuring and Related Activities [Abstract]
Restructuring	The Company incurred related restructuring charges as follows: (in thousands) Gross Net of Tax Q4 2016 $ 3,419 $ 2,355 Q1 2017 9,273 6,176 Q2 2017 2,000 1,435 Q3 2017 466 331 Total restructuring charges $ 15,158 $ 10,297

Organization - Additional Infor

Organization - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2018Segment
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of operating segments	1

Cash and Cash Equivalents (Deta

Cash and Cash Equivalents (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016
Accounting Policies [Abstract]
Cash accounts, Amount	$ 332,097	$ 568,587
Money market funds, Amount	397,083	312,914
Total	$ 729,180	$ 881,501	$ 919,571	$ 822,479
Cash accounts, % of Total	45.54%	64.50%
Money market funds, % of Total	54.46%	35.50%

Accounting Policies - Additiona

Accounting Policies - Additional Information (Detail)	Sep. 30, 2018	Dec. 31, 2017
Money Market Funds [Member]
Cash and Cash Equivalents [Line Items]
Concentration Risk, Percentage	100.00%	100.00%

Revenue from Contracts with C_3

Revenue from Contracts with Customers - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2018	Jan. 01, 2018
Total revenue	$ 289,418	$ 275,585	$ 878,204	$ 792,914
Cumulative Effect of New Accounting Principle in Period of Adoption						$ 183,100
Lease License to License Revenue			50.00%
Lease License to Maintenance Revenue			50.00%
Amount of Revenue Recognized From Beginning Deferred Revenue and Backlog			$ 334,400
Revenue, Remaining Performance Obligation, Amount	544,715		544,715
Minimum | Scenario, Forecast
2018 Tax Payments Related to the Adoption of ASC 606					$ 12,000
Maximum | Scenario, Forecast
2018 Tax Payments Related to the Adoption of ASC 606					$ 15,000
Gross impact
Cumulative Effect of New Accounting Principle in Period of Adoption						242,400
Deferred Revenue
Cumulative Effect of New Accounting Principle in Period of Adoption						$ 244,100
Calculated under Revenue Guidance in Effect before Topic 606
Total revenue	$ 301,956		$ 880,551

Impact of ASC 606 on Condensed

Impact of ASC 606 on Condensed Consolidated Financial Statement Line Items (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Accounts receivable, less allowance for doubtful accounts of $8,100	$ 235,547		$ 235,547		$ 124,659
Other receivables and current assets	162,629		162,629		263,820
Other long-term assets	53,226		53,226		35,972
Deferred income tax assets	22,285		22,285		42,111
Accrued income taxes	5,911		5,911		5,760
Other accrued expenses and liabilities	83,169		83,169		86,335
Deferred revenue - current	272,872		272,872		440,491
Deferred income tax liabilities	29,955		29,955		1,461
Other long-term liabilities	62,171		62,171		85,778
Stockholders' equity	2,548,546		2,548,546		$ 2,245,831
Total revenue	289,418	$ 275,585	878,204	$ 792,914
Total cost of sales	36,308	35,983	115,796	109,352
Income tax provision	$ 5,927	$ 34,295	$ 35,811	$ 86,698
Basic earnings per share	$ 1.06	$ 0.87	$ 3.17	$ 2.43
Diluted earnings per share	$ 1.04	$ 0.85	$ 3.09	$ 2.38
Accounting Standards Update 2014-09
Accounts receivable, less allowance for doubtful accounts of $8,100	$ 132,921		$ 132,921
Other receivables and current assets	(93,025)		(93,025)
Other long-term assets	14,556		14,556
Deferred income tax assets	(38,838)		(38,838)
Accrued income taxes	58		58
Other accrued expenses and liabilities	(1,667)		(1,667)
Deferred revenue - current	(161,257)		(161,257)
Deferred income tax liabilities	7,420		7,420
Other long-term liabilities	(10,837)		(10,837)
Stockholders' equity	181,897		181,897
Income tax provision	$ (1,758)		$ (278)
Basic earnings per share	$ (0.13)		$ (0.02)
Diluted earnings per share	$ (0.12)		$ (0.03)
Software licenses
Total revenue	$ 109,103	$ 156,580	$ 350,296	$ 448,368
Total cost of sales	4,291	7,395	12,301	24,197
Software licenses | Accounting Standards Update 2014-09
Total revenue	(57,503)		(132,360)
Total cost of sales	(4,197)		(12,777)
Maintenance and service
Total revenue	180,315	119,005	527,908	344,546
Total cost of sales	26,487	$ 19,584	80,092	$ 58,263
Maintenance and service | Accounting Standards Update 2014-09
Total revenue	44,965		130,013
Total cost of sales	4,197		12,777
Calculated under Revenue Guidance in Effect before Topic 606
Accounts receivable, less allowance for doubtful accounts of $8,100	102,626		102,626
Other receivables and current assets	255,654		255,654
Other long-term assets	38,670		38,670
Deferred income tax assets	61,123		61,123
Accrued income taxes	5,853		5,853
Other accrued expenses and liabilities	84,836		84,836
Deferred revenue - current	434,129		434,129
Deferred income tax liabilities	22,535		22,535
Other long-term liabilities	73,008		73,008
Stockholders' equity	2,366,649		2,366,649
Total revenue	301,956		880,551
Income tax provision	$ 7,685		$ 36,089
Basic earnings per share	$ 1.19		$ 3.19
Diluted earnings per share	$ 1.16		$ 3.12
Calculated under Revenue Guidance in Effect before Topic 606 | Software licenses
Total revenue	$ 166,606		$ 482,656
Total cost of sales	8,488		25,078
Calculated under Revenue Guidance in Effect before Topic 606 | Maintenance and service
Total revenue	135,350		397,895
Total cost of sales	$ 22,290		$ 67,315

Disaggregation of Revenue (Deta

Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Indirect sales channel revenue	24.46%	24.10%	23.86%	24.30%
Total revenue	$ 289,418	$ 275,585	$ 878,204	$ 792,914
Lease license
Total revenue	43,202	93,956	148,795	279,855
Perpetual license
Total revenue	65,901	62,624	201,501	168,513
Software licenses
Total revenue	109,103	156,580	350,296	448,368
Maintenance
Total revenue	171,463	112,300	500,962	324,338
Service
Total revenue	8,852	6,705	26,946	20,208
Maintenance and service
Total revenue	$ 180,315	$ 119,005	$ 527,908	$ 344,546
Calculated under Revenue Guidance in Effect before Topic 606
Indirect sales channel revenue	23.51%		23.46%
Total revenue	$ 301,956		$ 880,551
Calculated under Revenue Guidance in Effect before Topic 606 | Lease license
Total revenue	106,461		308,699
Calculated under Revenue Guidance in Effect before Topic 606 | Perpetual license
Total revenue	60,145		173,957
Calculated under Revenue Guidance in Effect before Topic 606 | Software licenses
Total revenue	166,606		482,656
Calculated under Revenue Guidance in Effect before Topic 606 | Maintenance
Total revenue	126,436		370,847
Calculated under Revenue Guidance in Effect before Topic 606 | Service
Total revenue	8,914		27,048
Calculated under Revenue Guidance in Effect before Topic 606 | Maintenance and service
Total revenue	$ 135,350		$ 397,895

Changes in Deferred Revenue (De

Changes in Deferred Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	May 02, 2018
Movement in Deferred Revenue [Roll Forward]
Acquired deferred revenue					$ 2,470
Recognition of deferred revenue	$ (289,418)	$ (275,585)	$ (878,204)	$ (792,914)
Deferral of revenue			868,522
Currency translation			(6,065)
Ending balance	$ 286,453		286,453
Balance at January 1st after ASC 606 Adoption
Movement in Deferred Revenue [Roll Forward]
Beginning balance			$ 299,730

Remaining Performance Obligatio

Remaining Performance Obligations, Expected Timing of Satisfaction (Details) $ in Thousands	Sep. 30, 2018USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Amount	$ 544,715
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2018-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Amount	$ 412,113
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	12 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Amount	$ 97,182
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	12 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Amount	$ 26,976
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	12 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Amount	$ 8,444
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period

Acquisition - Additional Inform

Acquisition - Additional Information (Detail) - USD ($) $ in Thousands	May 02, 2018	Sep. 30, 2018	Sep. 30, 2018
Percentage of shares acquired	100.00%
Business combination, consideration transferred	$ 290,983
Business combination, historical carrying value of acquired deferred revenue	14,200
Deferred revenue	2,470
Contract with customer, liability, increase (decrease) for contract acquired in business combination		$ 3,500	$ 6,200
Business acquisition write down of deferred revenue expected impact on revenue next quarter		2,500	2,500
Business acquisition write down of deferred revenue expected impact on revenue for fiscal year		8,700	8,700
Previous Accounting Guidance
Business combination, historical carrying value of acquired deferred revenue	$ 22,300
Contract with customer, liability, increase (decrease) for contract acquired in business combination		5,900	10,400
Business acquisition write down of deferred revenue expected impact on revenue next quarter		4,100	4,100
Business acquisition write down of deferred revenue expected impact on revenue for fiscal year		$ 14,500	14,500
OPTIS
Goodwill, period increase (decrease)			$ 2,100

Consideration Transferred (Deta

Consideration Transferred (Details) $ in Thousands	May 02, 2018USD ($)
Cash	$ 290,983

Recognized Amounts of Identifia

Recognized Amounts of Identifiable Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	Sep. 30, 2018	May 02, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016
Business Combination, Separately Recognized Transactions [Line Items]
Cash		$ 7,957
Accounts receivable and other tangible assets		16,026
Accounts payable and other liabilities		(13,396)
Deferred revenue		(2,470)
Net deferred tax liabilities		(21,576)
Total identifiable net assets		86,186
Goodwill	$ 1,575,567		$ 1,378,553	$ 1,353,444	$ 1,337,215
Developed Software and Core Technologies
Business Combination, Separately Recognized Transactions [Line Items]
Finite-lived intangible assets		47,593
Customer Lists and Contract Backlog
Business Combination, Separately Recognized Transactions [Line Items]
Finite-lived intangible assets		41,303
Trade Names
Business Combination, Separately Recognized Transactions [Line Items]
Finite-lived intangible assets		10,749
OPTIS
Business Combination, Separately Recognized Transactions [Line Items]
Goodwill		$ 204,797

Estimated Useful Lives (Details

Estimated Useful Lives (Details)	May 02, 2018	Sep. 30, 2018
Customer Lists and Contract Backlog
Finite-lived intangible asset, useful life	12 years
Minimum | Developed Software and Core Technologies
Finite-lived intangible asset, useful life	9 years	3 years
Minimum | Customer Lists and Contract Backlog
Finite-lived intangible asset, useful life		5 years
Minimum | Trade Names
Finite-lived intangible asset, useful life	4 years	2 years
Maximum | Developed Software and Core Technologies
Finite-lived intangible asset, useful life	10 years	11 years
Maximum | Customer Lists and Contract Backlog
Finite-lived intangible asset, useful life		15 years
Maximum | Trade Names
Finite-lived intangible asset, useful life	10 years	10 years

Pro Forma Information (Details)

Pro Forma Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenue	$ 289,418	$ 275,585	$ 878,204	$ 792,914
Operating income (loss)	93,024	$ 106,183	296,638	$ 290,049
OPTIS
Revenue	6,021		9,187
Operating income (loss)	(2,769)		(6,081)
Previous Accounting Guidance | OPTIS
Revenue	3,803		5,873
Operating income (loss)	$ (4,987)		$ (9,395)

Schedule of Receivables and Oth

Schedule of Receivables and Other Current Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Accounts receivable, less allowance for doubtful accounts of $8,100 and $6,800, respectively	$ 235,547	$ 124,659
Other receivables and current assets	162,629	263,820
Deferred Accounts Receivable Current Portion Of Lease Licenses And Software Maintenance [Member]
Other receivables and current assets	93,960	215,155
Taxes Receivable Related To Overpayments And Refunds [Member]
Other receivables and current assets	32,444	21,663
Prepaid Expenses and Other Current Assets [Member]
Other receivables and current assets	$ 36,225	$ 27,002

Receivables and Other Current_3

Receivables and Other Current Assets - Additional Information (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Jan. 01, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, less allowance for doubtful accounts of $8,100 and $6,800, respectively	$ 235,547		$ 124,659
Other receivables and current assets	162,629		263,820
Balance at January 1st after ASC 606 Adoption
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, less allowance for doubtful accounts of $8,100 and $6,800, respectively		$ 278,800
Deferred Accounts Receivable Current Portion Of Lease Licenses And Software Maintenance [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Other receivables and current assets	$ 93,960		$ 215,155
Deferred Accounts Receivable Current Portion Of Lease Licenses And Software Maintenance [Member] | Balance at January 1st after ASC 606 Adoption
Accounts, Notes, Loans and Financing Receivable [Line Items]
Other receivables and current assets		$ 136,400

Details of Basic and Diluted EP

Details of Basic and Diluted EPS (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share [Abstract]
Net income	$ 89,336	$ 73,630	$ 266,212	$ 206,666
Weighted average shares outstanding - basic	84,158	84,774	84,065	85,132
Dilutive effect of stock plans	1,885	1,814	1,995	1,770
Weighted average shares outstanding - diluted	86,043	86,588	86,060	86,902
Basic earnings per share	$ 1.06	$ 0.87	$ 3.17	$ 2.43
Diluted earnings per share	$ 1.04	$ 0.85	$ 3.09	$ 2.38
Anti-dilutive shares	0	27	0	112

Intangible Assets (Detail)

Intangible Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Intangible Assets [Line Items]
Amortized intangible assets, gross carrying amount	$ 757,980	$ 663,565
Amortized intangible assets, accumulated amortization	(538,773)	(506,297)
Indefinite-lived intangible assets (excluding goodwill)	357
Trade Names
Intangible Assets [Line Items]
Indefinite-lived intangible assets (excluding goodwill)	357	357
Developed Software and Core Technologies
Intangible Assets [Line Items]
Amortized intangible assets, gross carrying amount	411,406	365,317
Amortized intangible assets, accumulated amortization	(311,938)	(297,645)
Customer Lists and Contract Backlog
Intangible Assets [Line Items]
Amortized intangible assets, gross carrying amount	209,172	171,048
Amortized intangible assets, accumulated amortization	(113,881)	(104,522)
Trade Names
Intangible Assets [Line Items]
Amortized intangible assets, gross carrying amount	137,402	127,200
Amortized intangible assets, accumulated amortization	$ (112,954)	$ (104,130)

Estimated Useful Lives (Detail)

Estimated Useful Lives (Detail)	May 02, 2018	Sep. 30, 2018
Customer Lists and Contract Backlog
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life	12 years
Minimum | Developed Software and Core Technologies
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life	9 years	3 years
Minimum | Customer Lists and Contract Backlog
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life		5 years
Minimum | Trade names
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life	4 years	2 years
Maximum | Developed Software and Core Technologies
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life	10 years	11 years
Maximum | Customer Lists and Contract Backlog
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life		15 years
Maximum | Trade names
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life	10 years	10 years

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization	$ 9,021	$ 12,264	$ 33,824	$ 36,398

Estimated Future Amortization E

Estimated Future Amortization Expense for Intangible Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Remainder of 2018	$ 7,142
2,019	31,618
2,020	32,823
2,021	30,029
2,022	26,342
2,023	23,429
Thereafter	67,824
Total intangible assets subject to amortization	219,207
Indefinite-lived intangible assets (excluding goodwill)	357
Other intangible assets, net	$ 219,564	$ 157,625

Changes in Goodwill (Detail)

Changes in Goodwill (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Goodwill [Roll Forward]
Beginning balance	$ 1,378,553	$ 1,337,215
Acquisitions and adjustments	204,271	11,719
Currency translation	(7,257)	4,510
Ending balance	$ 1,575,567	$ 1,353,444

Fair Value of Assets and Liabil

Fair Value of Assets and Liabilities Measured on Recurring Basis (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	$ 397,083	$ 312,914
Short-term investments	211	286
Deferred compensation plan investments	1,840	3,742
Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	397,083	312,914
Short-term investments	0	0
Deferred compensation plan investments	1,840	3,742
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Short-term investments	211	286
Deferred compensation plan investments	0	0
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Short-term investments	0	0
Deferred compensation plan investments	$ 0	$ 0

Fair Value Measurement - Additi

Fair Value Measurement - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2018
Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments maturity	3 months
Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments maturity	1 year

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Jun. 30, 2018	Sep. 30, 2018	Sep. 30, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Transition Tax, Amount		$ 900	$ 16,900	$ 16,000
Transition Tax Payment		15,700
Accrued Income Taxes, Noncurrent		1,200	1,200
Foreign Earnings Repatriated	$ 144,300
Unrecognized Tax Benefits		$ 30,200	$ 30,200

Revenue by Geographic Area (Det

Revenue by Geographic Area (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 289,418	$ 275,585	$ 878,204	$ 792,914
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	106,229	105,480	327,784	305,661
Japan
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	36,309	30,779	109,050	94,612
Germany
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	27,831	28,395	97,262	79,160
China
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	14,568	14,043	38,616	35,429
France
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	14,035	13,438	44,638	37,997
South Korea
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	12,943	15,292	45,468	45,633
Other EMEA
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	45,602	40,887	136,719	116,844
Other international
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	31,901	$ 27,271	78,667	$ 77,578
Calculated under Revenue Guidance in Effect before Topic 606
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	301,956		880,551
Calculated under Revenue Guidance in Effect before Topic 606 | United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	121,131		345,886
Calculated under Revenue Guidance in Effect before Topic 606 | Japan
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	33,331		101,789
Calculated under Revenue Guidance in Effect before Topic 606 | Germany
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	30,728		92,262
Calculated under Revenue Guidance in Effect before Topic 606 | China
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	14,703		37,870
Calculated under Revenue Guidance in Effect before Topic 606 | France
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	15,116		45,511
Calculated under Revenue Guidance in Effect before Topic 606 | South Korea
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	14,068		46,305
Calculated under Revenue Guidance in Effect before Topic 606 | Other EMEA
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	43,066		132,482
Calculated under Revenue Guidance in Effect before Topic 606 | Other international
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 29,813		$ 78,446

Property and Equipment by Geogr

Property and Equipment by Geographic Area (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property and equipment, net	$ 57,902	$ 57,096
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property and equipment, net	44,117	45,498
India
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property and equipment, net	3,708	3,704
EMEA
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property and equipment, net	6,326	5,114
Other international
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property and equipment, net	$ 3,751	$ 2,780

Stock-Based Compensation Expens

Stock-Based Compensation Expense and Its Net Impact on Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Employee Service Share-Based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense before taxes	$ 22,983	$ 14,773	$ 58,887	$ 39,408
Related income tax benefits	(8,611)	(6,080)	(30,311)	(23,980)
Stock-based compensation expense, net of taxes	$ 14,372	$ 8,693	$ 28,576	$ 15,428
Basic earnings per share	$ (0.17)	$ (0.10)	$ (0.34)	$ (0.18)
Diluted earnings per share	$ (0.17)	$ (0.10)	$ (0.33)	$ (0.18)
Software Licenses
Employee Service Share-Based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense before taxes	$ 0	$ 140	$ 0	$ 711
Maintenance and Service
Employee Service Share-Based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense before taxes	1,438	739	3,880	1,894
Selling, General and Administrative
Employee Service Share-Based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense before taxes	13,484	8,782	33,288	23,310
Research and Development
Employee Service Share-Based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense before taxes	$ 8,061	$ 5,112	$ 21,719	$ 13,493

Stock Repurchase Program (Detai

Stock Repurchase Program (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Class of Stock Disclosures [Abstract]
Number of shares repurchased	1,174	2,000
Average price paid per share	$ 164.14	$ 111.65
Total cost	$ 192,787	$ 223,291

Stock Repurchase Program - Addi

Stock Repurchase Program - Additional Information (Detail) shares in Millions	Sep. 30, 2018shares
Class of Stock Disclosures [Abstract]
Stock repurchase program, repurchase authorization	5
Stock repurchase program, remaining number of shares authorized to be repurchased	4.3

Restructuring (Detail)

Restructuring (Detail) - USD ($) $ in Thousands	3 Months Ended				12 Months Ended
	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 331	$ 1,435	$ 6,176	$ 2,355	$ 10,297
Operating Income (Loss) [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 466	$ 2,000	$ 9,273	$ 3,419	$ 15,158

Contingencies and Commitments -

Contingencies and Commitments - Additional Information (Detail) $ in Millions	Sep. 30, 2018USD ($)
India Service Tax Audit [Member]
Loss Contingencies [Line Items]
Loss contingency, estimate of possible loss	$ 6.8