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Document and Entity Information - USD ($)	12 Months Ended
Document and Entity Information - USD ($)	Dec. 31, 2016	Feb. 14, 2017	Jun. 30, 2016
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2016
Document Fiscal Year Focus	2016
Document Fiscal Period Focus	FY
Trading Symbol	ANSS
Entity Registrant Name	ANSYS INC
Entity Central Index Key	0001013462
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		85,373,363
Entity Well-Known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 6,086,000,000

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 822,479	$ 784,168
Short-term investments	381	446
Accounts receivable, less allowance for doubtful accounts of $5,700 and $5,200, respectively	107,192	91,579
Other receivables and current assets	239,349	200,233
Total current assets	1,169,401	1,076,426
Property and equipment, net	54,677	61,924
Goodwill	1,337,215	1,332,348
Other intangible assets, net	172,619	220,553
Other long-term assets	24,287	5,757
Deferred income taxes	42,327	32,896
Total assets	2,800,526	2,729,904
Current liabilities:
Accounts payable	7,395	4,865
Accrued bonuses and commissions	49,487	46,141
Accrued income taxes	5,263	4,695
Other accrued expenses and liabilities	73,676	63,801
Deferred revenue	403,279	364,644
Total current liabilities	539,100	484,146
Long-term liabilities:
Deferred income taxes	2,259	2,091
Other long-term liabilities	50,762	49,240
Total long-term liabilities	53,021	51,331
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	883,010	894,469
Retained earnings	2,057,665	1,792,029
Treasury stock, at cost: 7,548,188 and 5,096,505 shares, respectively	(675,550)	(440,839)
Accumulated other comprehensive loss	(57,652)	(52,164)
Total stockholders’ equity	2,208,405	2,194,427
Total liabilities and stockholders’ equity	$ 2,800,526	$ 2,729,904

CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenue:
Software licenses	$ 568,174	$ 555,105	$ 564,502
Maintenance and service	420,291	387,648	371,519
Total revenue	988,465	942,753	936,021
Cost of sales:
Software licenses	28,860	29,105	30,607
Amortization	38,092	38,755	37,653
Maintenance and service	79,908	79,386	85,126
Total cost of sales	146,860	147,246	153,386
Gross profit	841,605	795,507	782,635
Operating expenses:
Selling, general and administrative	269,515	253,603	246,376
Research and development	183,093	168,831	165,421
Amortization	12,755	19,394	23,388
Total operating expenses	465,363	441,828	435,185
Operating income	376,242	353,679	347,450
Interest expense	(221)	(325)	(779)
Interest income	4,209	2,829	3,002
Other income (expense), net	85	582	(1,534)
Income before income tax provision	380,315	356,765	348,139
Income tax provision	114,679	104,244	93,449
Net income	$ 265,636	$ 252,521	$ 254,690
Earnings per share – basic:
Earnings per share	$ 3.05	$ 2.82	$ 2.77
Weighted average shares	87,227	89,561	92,067
Earnings per share – diluted:
Earnings per share	$ 2.99	$ 2.76	$ 2.70
Weighted average shares	88,969	91,502	94,194

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 5,700	$ 5,200
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	7,548,188	5,096,505

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Comprehensive Income [Abstract]
Net income	$ 265,636	$ 252,521	$ 254,690
Other comprehensive loss:
Foreign currency translation adjustments	(5,488)	(20,410)	(29,110)
Comprehensive income	$ 260,148	$ 232,111	$ 225,580

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash flows from operating activities:
Net income	$ 265,636	$ 252,521	$ 254,690
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	69,587	77,670	81,924
Deferred income tax benefit	(10,921)	(15,196)	(18,859)
Provision for bad debts	2,009	1,304	2,104
Stock-based compensation expense	33,347	33,951	36,861
Excess tax benefits from stock-based compensation	(9,153)	(8,176)	(14,531)
Other	1,290	1,413	868
Changes in operating assets and liabilities:
Accounts receivable	(17,388)	6,044	(5,554)
Other receivables and current assets	(39,644)	(17,662)	(877)
Other long-term assets	(7,167)	273	(1,838)
Accounts payable, accrued expenses and current liabilities	16,919	(6,993)	8,208
Accrued income taxes	9,052	5,770	12,102
Deferred revenue	41,430	40,566	35,548
Other long-term liabilities	1,830	(3,962)	(5,339)
Net cash provided by operating activities	356,827	367,523	385,307
Cash flows from investing activities:
Acquisitions, net of cash acquired	(7,891)	(46,117)	(103,016)
Capital expenditures	(12,443)	(16,145)	(26,023)
Other investing activities	(11,839)	230	(231)
Net cash used in investing activities	(32,173)	(62,032)	(129,270)
Cash flows from financing activities:
Purchase of treasury stock	(336,335)	(337,910)	(233,793)
Restricted stock withholding taxes paid in lieu of issued shares	(5,057)	(4,446)	(5,108)
Contingent consideration payments	(1,048)	(1,173)	(4,504)
Proceeds from shares issued for stock-based compensation	53,811	43,623	43,323
Excess tax benefits from stock-based compensation	9,153	8,176	14,531
Other financing activities	(1)	(21)	(91)
Net cash used in financing activities	(279,477)	(291,751)	(185,642)
Effect of exchange rate fluctuations on cash and cash equivalents	(6,866)	(17,636)	(24,817)
Net increase (decrease) in cash and cash equivalents	38,311	(3,896)	45,578
Cash and cash equivalents, beginning of period	784,168	788,064	742,486
Cash and cash equivalents, end of period	822,479	784,168	788,064
Supplemental disclosures of cash flow information:
Income taxes paid	118,455	107,218	118,004
Interest paid	822	620	643
Fair value of stock options and restricted stock awards assumed in connection with acquisitions	0	3,528	68
Construction-in-progress - leased facility	$ 0	$ 0	$ (18,136)

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Loss
Beginning balance at Dec. 31, 2013	$ 2,136,246	$ 932	$ 926,031	$ 1,284,818	$ (72,891)	$ (2,644)
Beginning balance, shares at Dec. 31, 2013		93,236			918
Treasury shares acquired	$ (233,793)				$ (233,793)
Treasury shares acquired, shares	2,977				2,977
Stock-based compensation activity, including tax benefit	$ 90,046		(20,628)		$ 110,674
Stock-based compensation activity, including tax benefit, shares					(1,424)
Other comprehensive loss	(29,110)					(29,110)
Net income for the year	254,690			254,690
Acquisition-related activity	(578)		(578)
Ending balance at Dec. 31, 2014	2,217,501	$ 932	904,825	1,539,508	$ (196,010)	(31,754)
Ending balance, shares at Dec. 31, 2014		93,236			2,471
Treasury shares acquired	$ (337,910)				$ (337,910)
Treasury shares acquired, shares	3,833				3,833
Stock-based compensation activity, including tax benefit	$ 79,197		(8,434)		$ 87,631
Stock-based compensation activity, including tax benefit, shares					(1,139)
Other comprehensive loss	(20,410)					(20,410)
Net income for the year	252,521			252,521
Acquisition-related activity	3,528		(1,922)		$ 5,450
Acquisition-related activity, shares					(68)
Ending balance at Dec. 31, 2015	2,194,427	$ 932	894,469	1,792,029	$ (440,839)	(52,164)
Ending balance, shares at Dec. 31, 2015		93,236			5,097
Treasury shares acquired	$ (336,335)				$ (336,335)
Treasury shares acquired, shares	3,700				3,700
Stock-based compensation activity, including tax benefit	$ 90,165		(11,459)		$ 101,624
Stock-based compensation activity, including tax benefit, shares					(1,249)
Other comprehensive loss	(5,488)					(5,488)
Net income for the year	265,636			265,636
Ending balance at Dec. 31, 2016	$ 2,208,405	$ 932	$ 883,010	$ 2,057,665	$ (675,550)	$ (57,652)
Ending balance, shares at Dec. 31, 2016		93,236			7,548

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (PARENTHETICAL) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Stockholders' Equity [Abstract]
Stock-based compensation activity, tax benefit	$ 8,065	$ 6,068	$ 14,970

Organization	12 Months Ended
Organization	Dec. 31, 2016
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 technologies widely used by engineers, designers, researchers and students across a broad spectrum of industries and academia, including aerospace and defense, automotive, industrial equipment, electronics, biomedical, energy, materials and chemical processing, and semiconductors. 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

12 Months Ended

Dec. 31, 2016

Accounting Policies [Abstract]

Accounting Policies

Accounting Principles

The financial statements and accompanying notes are prepared in accordance with accounting principles generally accepted in the United States.

Principles of Consolidation

The accompanying consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany accounts and transactions have been eliminated.

Use of Estimates

The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements. Estimates also affect the amounts of revenue and expenses during the reported periods. Significant estimates included in these consolidated financial statements include:


•	Allowances for doubtful accounts receivable


•	Income tax accruals


•	Uncertain tax positions


•	Tax valuation reserves


•	Fair value of stock-based compensation


•	Contract revenue


•	Useful lives for depreciation and amortization


•	Valuations of goodwill and other intangible assets


•	Contingent consideration


•	Deferred compensation


•	Loss contingencies

Actual results could differ from these estimates. Changes in estimates are recorded in the results of operations in the period that the changes occur.

Revenue Recognition

Revenue is derived principally from the licensing of computer software products and from related maintenance contracts. Revenue from perpetual licenses is classified as license revenue and is recognized upon delivery of the licensed product and the utility that enables the customer to access authorization keys, provided that acceptance has occurred and a signed contractual obligation has been received, the price is fixed and determinable, and collectibility of the receivable is probable. The Company determines the fair value of PCS sold together with perpetual licenses based on the rate charged for PCS when sold separately. Revenue from PCS contracts is classified as maintenance and service revenue and is recognized ratably over the term of the contract.

Revenue for software lease licenses is classified as license revenue and is recognized over the period of the lease contract. Typically, the Company's software leases include PCS which, due to the short term (principally one year or less) of the Company's software lease licenses, cannot be separated from lease revenue for accounting purposes. As a result, both the lease licenses and PCS are recognized ratably over the lease period. Due to the short-term nature of the software lease licenses and the frequency with which the Company provides major product upgrades (typically annually), the Company does not believe that a significant portion of the fee paid under the arrangement is attributable to the PCS component of the arrangement and, as a result, includes the revenue for the entire arrangement within software license revenue in the consolidated statements of income.

Many of the Company's semiconductor products are typically licensed via longer term leases of 24–36 months. The Company recognizes revenue for these licenses over the term of the lease contract. Because the Company does not have vendor-specific objective evidence of the fair value of these leases, the Company also recognizes revenue from perpetual licenses over the term of the lease contract during the infrequent occurrence of these licenses being sold with semiconductor leases in multiple-element arrangements.

Revenue from training, support and other services is recognized as the services are performed. The Company applies the specific performance method to contracts in which the service consists of a single act, such as providing a training class to a customer, and the proportional performance method to other service contracts that are longer in duration and often include multiple acts (for example, both training and consulting). In applying the proportional performance method, 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 written purchase commitment, collectibility from the channel partner is probable, a license agreement signed by the end-user customer is received and delivery has occurred, 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 based on the rate charged for PCS when sold separately, and is recognized over the period that PCS is to be provided. The Company does not offer right of return, product rotation or price protection to any of its channel partners.

Non-income related taxes collected from customers and remitted to governmental authorities are recorded on the consolidated balance sheet as accounts receivable and accrued expenses. The collection and payment of these amounts are reported on a net basis in the consolidated statements of income and do not impact reported revenues or expenses.

The Company warrants to its customers that its software will substantially perform as specified in the Company's most 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. Consequently, the Company has not established reserves for warranty obligations.

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 with original maturities of three months or less. Cash equivalents are carried at cost, which approximates fair value. The Company's cash and cash equivalents balances comprise the following:



	December 31, 2016			December 31, 2015
(in thousands, except percentages)	Amount		% of Total	Amount		% of Total
Cash accounts	$	488,504	59.4	$	427,244	54.5
Money market funds	333,975		40.6	356,924		45.5
Total	$	822,479		$	784,168

The Company's money market fund balances are held in various funds of a single issuer.

Property and Equipment

Property and equipment is stated at cost. Depreciation is computed using the straight-line method over the estimated useful lives of the various classes of assets, which range from one to forty years. Repairs and maintenance are charged to expense as incurred. Gains or losses from the sale or retirement of property and equipment are included in operating income.

Research and Development

Research and development costs, other than certain capitalized software development costs, are expensed as incurred.

Software Development Costs

Internally developed software costs required to be capitalized as defined by the accounting guidance are not material to the Company's consolidated financial statements.

Business Combinations

When the Company consummates an acquisition, the assets acquired and the liabilities assumed are recognized separately from goodwill at their acquisition date fair values. Goodwill as of the acquisition date is measured as the excess of the fair value of consideration transferred over the net of the acquisition date fair values of the assets acquired and the liabilities assumed. While best estimates and assumptions are used to accurately value assets acquired and liabilities assumed at the acquisition date as well as contingent consideration, where applicable, the Company's estimates are inherently uncertain and subject to refinement. As a result, during the measurement period, which may be up to one year from the acquisition date, the Company records adjustments to the assets acquired and liabilities assumed with the corresponding offset to goodwill as the Company obtains 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. Upon the earlier of the conclusion of the measurement period or final determination of the values of assets acquired or liabilities assumed, any subsequent adjustments are recorded in the consolidated statements of income.

Goodwill and Other Intangible Assets

Goodwill represents the excess of the consideration transferred over the fair value of net identifiable assets acquired. Other intangible assets consist of trade names, customer lists, contract backlog and acquired software and technology. Intangible assets that are not considered to have an indefinite useful life are amortized over their useful lives, which are generally two to fifteen years. Amortization expense for intangible assets was $50.8 million, $58.1 million and $61.0 million for the years ended December 31, 2016, 2015 and 2014, respectively.

The Company tests goodwill and indefinite-lived intangible assets for impairment at least annually by performing a quantitative assessment of whether the fair value of each reporting unit or asset exceeds its carrying amount. Goodwill is tested at the reporting unit level and indefinite-lived intangible assets are tested at the individual asset level. This requires the Company to assess and make judgments regarding a variety of factors which impact the fair value of the reporting unit or asset being tested, including business plans, anticipated future cash flows, economic projections and other market data.

The Company performs its annual impairment tests for goodwill and indefinite-lived intangible assets on January 1 of each year unless there is an indicator that would require a test during the year. The Company periodically reviews the carrying value of other intangible assets and will recognize impairments when events or circumstances indicate that such assets may be impaired.

Concentrations of Credit Risk

The Company has a concentration of credit risk with respect to revenue and trade receivables due to the use of certain significant channel partners to market and sell the Company's products. The Company performs periodic credit evaluations of its customers' financial condition and generally does not require collateral. The following table outlines concentrations of risk with respect to the Company's revenue:



	Year Ended December 31,
(as a % of revenue)	2016		2015		2014
Revenue from channel partners	24	%	24	%	25	%
Largest channel partner	5	%	5	%	4	%
2^nd largest channel partner	2	%	2	%	2	%

No single customer accounted for more than 5% of the Company's revenue in 2016, 2015 or 2014.

In addition to the concentration of credit risk with respect to trade receivables, the Company's cash and cash equivalents are also exposed to concentration of credit risk. The Company's cash and cash equivalent accounts are insured through various public and private bank deposit insurance programs, foreign and domestic; however, a significant portion of the Company's funds are not insured. The following table outlines concentrations of risk with respect to the Company's cash and cash equivalents:



	As of December 31,
(in thousands)	2016		2015
Cash and cash equivalents held domestically	$	593,348	$	539,031
Cash and cash equivalents held by foreign subsidiaries	229,131		245,137
Cash and cash equivalents held in excess of deposit insurance, foreign and domestic	805,374		763,400
Largest balance of cash and cash equivalents held with one financial institution, foreign and domestic	377,602		440,650

Allowance for Doubtful Accounts

The Company makes judgments as to its ability to collect outstanding receivables and provides allowances for a portion of receivables when collection becomes doubtful. Provisions are made based upon a specific review of all significant outstanding invoices from both value and delinquency perspectives. For those invoices not specifically reviewed, provisions are estimated at differing rates based upon the age of the receivable and the geographic area of origin. In determining these percentages, the Company considers its historical collection experience and current economic trends in the customer's industry and geographic region. The Company recorded provisions for doubtful accounts of $2.0 million, $1.3 million and $2.1 million for the years ended December 31, 2016, 2015 and 2014, respectively.

Income Taxes

The Company accounts for income taxes under the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements. Under this method, deferred tax assets and liabilities are determined based on the differences between the financial statement and tax bases of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in income in the period of the enactment date.

The Company records net deferred tax assets to the extent it believes these assets will more likely than not be realized. In making such determination, the Company considers all available positive and negative evidence, including scheduled reversals of deferred tax liabilities, projected future taxable income, tax planning strategies and recent financial operations. In the event the Company determines that it will be able to realize deferred tax assets for which a valuation allowance was used to reduce their carrying value, the adjustment to the valuation allowance will be recorded as a reduction to the provision for income taxes.

Tax benefits related to uncertain tax positions taken or expected to be taken on a tax return are recorded when such benefits meet a more-likely-than-not threshold. Otherwise, these tax benefits are recorded when a tax position has been effectively settled, which means that the statute of limitations has expired or the appropriate taxing authority has completed their examination even though the statute of limitations remains open. The Company recognizes interest and penalties related to income taxes within the income tax expense line in the accompanying consolidated statements of income. Accrued interest and penalties are included within the related tax liability line in the consolidated balance sheets.

Foreign Currencies

Certain of the Company's sales and intercompany transactions are denominated in foreign currencies. These transactions are translated to the functional currency at the exchange rate on the transaction date. Assets and liabilities denominated in a currency other than the Company's or subsidiary's functional currency are translated at the effective exchange rate on the balance sheet date. Gains and losses resulting from foreign exchange transactions are included in other income (expense), net. The Company recorded net foreign exchange gains of $0.1 million and $0.5 million for the years ended December 31, 2016 and 2015, respectively, and net foreign exchange losses of $1.6 million for the year ended December 31, 2014.

The financial statements of the Company's foreign subsidiaries are translated from the functional (local) currency to U.S. Dollars. Assets and liabilities are translated at the exchange rates on the balance sheet date. Results of operations are translated at average exchange rates, which approximate rates in effect when the underlying transactions occurred.

Accumulated Other Comprehensive Loss

Accumulated other comprehensive loss is composed entirely of foreign currency translation adjustments.

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 options are anti-dilutive, they are excluded from the calculation of diluted EPS.

The details of basic and diluted EPS are as follows:



	Year Ended December 31,
(in thousands, except per share data)	2016		2015		2014
Net income	$	265,636	$	252,521	$	254,690
Weighted average shares outstanding – basic	87,227		89,561		92,067
Dilutive effect of stock plans	1,742		1,941		2,127
Weighted average shares outstanding – diluted	88,969		91,502		94,194
Basic earnings per share	$	3.05	$	2.82	$	2.77
Diluted earnings per share	$	2.99	$	2.76	$	2.70
Anti-dilutive options	260		206		718

Stock-Based Compensation

The Company accounts for stock-based compensation in accordance with share-based payment accounting guidance. The guidance requires an entity to measure the cost of employee services received in exchange for an award of equity instruments based on the grant-date fair value of the award. The cost is recognized over the period during which an employee is required to provide service in exchange for the award, typically the vesting period.

Fair Value of Financial Instruments

The Company accounts for certain assets and liabilities at fair value in accordance with the accounting guidance applicable to fair value measurements and disclosures. The carrying values of cash, cash equivalents, short-term investments, accounts receivable, accounts payable, accrued expenses, other accrued liabilities and short-term obligations are deemed to be reasonable estimates of their fair values because of their short-term nature.

New Accounting Guidance

Business combinations: In January 2017, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update No. 2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business (ASU 2017-01). This update 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 update 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. ASU 2017-01 is effective for annual periods beginning after December 15, 2017, including interim periods within that reporting period. Early adoption is permitted and the update will be applied prospectively. The effect of the implementation will depend upon the nature of the Company's future acquisitions, if any. Historically, the Company has entered into acquisitions that would meet the definition of a business under ASU 2017-01.

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). Previous guidance requires the tax effects from intra-entity asset transfers to be deferred until that asset is sold to a third party or recovered through use. ASU 2016-16 eliminates this deferral for all intra-entity asset transfers other than inventory. The standard is effective for annual periods beginning after December 15, 2017, including interim periods within that reporting period. Early adoption is permitted and a modified retrospective transition is required upon adoption. The Company plans to adopt ASU 2016-16 beginning in 2018 and expects adoption to have an immaterial effect, if any, on its financial results.

Employee share-based payment accounting: In March 2016, the FASB issued Accounting Standards Update No. 2016-09, Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting (ASU 2016-09). This update includes various areas for simplification related to aspects of the accounting for share-based payment transactions. One simplification is that the tax effects of share-based payment settlements will be recorded in the income statement. Prior guidance required tax windfalls at settlement, and tax shortfalls to the extent of previous windfalls, to be recorded in equity. This provision is required to be adopted prospectively. These tax effects will be reported as operating cash flows according to the new guidance as opposed to financing cash flows in the prior guidance. Other simplifications involve the classification of awards as either equity or liabilities and classification on the statements of cash flows. ASU 2016-09 is effective for annual periods beginning after December 15, 2016, including interim periods within that reporting period. The primary impact of adoption will be the recognition of excess tax benefits or deficiencies in the Company's provision for income taxes rather than paid-in capital, and the related change in classification of such benefits on the consolidated statements of cash flows.

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, to be recorded on the balance sheet with a right-of-use asset and corresponding lease liability. As a result, the Company's assets and liabilities will increase upon adoption. 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. Early adoption is permitted and a modified retrospective transition is required upon adoption. The Company does not expect to early adopt and is currently in the data-gathering phase of implementation. The Company is currently evaluating the effect that implementation of this update will have on its financial results upon adoption.

Revenue from contracts with customers: In May 2014, the FASB issued Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers (Topic 606) (ASU 2014-09). ASU 2014-09 supersedes most current revenue recognition guidance, including industry-specific guidance. Previous guidance requires an entity to recognize revenue when persuasive evidence of an arrangement exists, delivery has occurred or services have been rendered, the seller's price to the buyer is fixed or determinable, and collectibility is reasonably assured. Under the new guidance, an entity is required 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 standard also requires disclosure of the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers.

ASU 2015-14, Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date, delayed the effective date of ASU 2014-09 to annual periods beginning after December 15, 2017, including interim periods within that reporting period. This standard is effective for the Company on January 1, 2018. Entities have the option of using a full retrospective, cumulative effect or modified approach to adopt ASU 2014-09. The Company expects to utilize the full retrospective method to restate each prior period presented upon adoption.

This update will impact the timing and amounts of revenue recognized. The Company's preliminary assessment is that the adoption of this standard will have a material impact on the Company’s consolidated financial statements. While the Company expects that the standard will impact various elements of its business, the Company's initial assessment is that the most significant impact will be on the recognition of revenue related to software lease licenses. These licenses include the right to use the software and PCS over the term of the license. These licenses are currently recognized as revenue ratably over the term of the license. Under the new standard and the existing interpretations, the Company expects to recognize a meaningful portion of the revenue related to these licenses up-front at the time the license is delivered. However, the Company's preliminary assessment could change as additional interpretations relating to the new standard are provided and as issues identified by software industry groups are addressed.

Acquisitions

12 Months Ended

Dec. 31, 2016

Business Combinations [Abstract]

Acquisitions

During the twelve months ended December 31, 2016 and 2015, the Company completed various acquisitions to accelerate the development of new and innovative products to the marketplace while lowering design and engineering costs for customers. The acquisitions were not individually significant. The combined purchase prices of the acquisitions were approximately $10.3 million and $49.7 million for the years ended December 31, 2016 and 2015, respectively.

The operating results of each acquisition have been included in the Company's consolidated financial statements since each respective date of acquisition. The effects of the business combinations were not material to the Company's consolidated results of operations individually or in the aggregate.

In valuing deferred revenue on the balance sheets of the Company's 2016 and 2015 acquisitions as of their respective acquisition dates, the Company applied the fair value provisions applicable to the accounting for business combinations, resulting in a reduction of deferred revenue as compared to the historical carrying amounts. During 2015, acquired deferred revenues with a combined historical carrying value of $0.9 million were ascribed no fair value on the opening balance sheets. 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 each acquiree absent the acquisitions. The impacts on reported revenue for the years ended December 31, 2016 and 2015 were $0.1 million and $0.8 million, respectively.

SpaceClaim Corporation

On April 30, 2014, the Company completed the acquisition of SpaceClaim, a leading provider of 3-D modeling technology. Under the terms of the agreement, ANSYS acquired SpaceClaim for a purchase price of $85.0 million, which was paid almost entirely in cash.

SpaceClaim's software provides customers with a powerful and intuitive 3-D direct modeling solution to author new concepts and then leverage the power of simulation to rapidly iterate on these designs to drive innovation. The broad appeal of the SpaceClaim technology can help the Company deliver simulation tools to any engineer in any industry. The complementary combination accelerates the development of new and innovative products to the marketplace while lowering design and engineering costs for customers.

The operating results of SpaceClaim have been included in the Company's consolidated financial statements from April 30, 2014, the date of acquisition.

The assets and liabilities of SpaceClaim 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, as adjusted within the one-year measurement period:

Fair Value of Consideration Transferred:



(in thousands)
Cash	$	84,892
ANSYS replacement stock options	68
Total consideration transferred at fair value	$	84,960

Recognized Amounts of Identifiable Assets Acquired and Liabilities Assumed:



(in thousands)
Cash	$	723
Accounts receivable and other tangible assets	1,857
Developed technology (10-year life)	15,800
Customer relationships (6-year life)	9,400
Trade name (6-year life)	1,300
Contract backlog (6-year life)	550
Non-compete agreement (2-year life)	300
Net deferred tax assets	9,288
Accounts payable and other liabilities	(2,011		)
Deferred revenue	(700		)
Total identifiable net assets	$	36,507
Goodwill	$	48,453

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 SpaceClaim.

During the one-year measurement period since the SpaceClaim acquisition date, the Company adjusted the fair values of the assets acquired and liabilities assumed, with the offset recorded as a $4.8 million decrease to goodwill. These adjustments were made 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.

In valuing deferred revenue on the SpaceClaim 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 $3.3 million was ascribed a fair value of $0.7 million on the opening balance sheet. As a result, the Company's post-acquisition revenue was less than the sum of what would have otherwise been reported by ANSYS and SpaceClaim absent the acquisition. The impacts on reported revenue for the twelve months ended December 31, 2015 and 2014 were $0.6 million and $2.0 million, respectively.

Reaction Design

On January 3, 2014, the Company completed the acquisition of Reaction Design, a leading developer of chemistry simulation software. Under the terms of the agreement, ANSYS acquired Reaction Design for a purchase price of $19.1 million in cash. Reaction Design's solutions enable transportation manufacturers and energy companies to rapidly achieve their clean technology goals by automating the analysis of chemical processes via computer simulation and modeling solutions.

The operating results of Reaction Design have been included in the Company's consolidated financial statements since the date of acquisition, January 3, 2014. The total consideration transferred was allocated to the assets and liabilities of Reaction Design based on management's estimates of the fair values of the assets acquired and the liabilities assumed. The allocation included $7.0 million to identifiable intangible assets, including core technology, customer lists and trade names, to be amortized over periods between two and eleven years, and $9.2 million to goodwill, which is not tax-deductible. These amounts include measurement-period adjustments. During the one-year measurement period since the Reaction Design acquisition date, the Company adjusted the fair values of the assets acquired and liabilities assumed, with the offset recorded as an increase to goodwill of $1.9 million and a reduction in noncontrolling interest of $0.6 million. These adjustments were made 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.

In valuing deferred revenue on the Reaction Design 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 $2.3 million was ascribed no fair value on the opening balance sheet. As a result, the Company's post-acquisition revenue was less than the sum of what would have otherwise been reported by ANSYS and Reaction Design absent the acquisition. The impacts on reported revenue for the twelve months ended December 31, 2015 and 2014 were $0.3 million and $2.0 million, respectively.

- Definition

The entire disclosure for a business combination (or series of individually immaterial business combinations) completed during the period, including background, timing, and recognized assets and liabilities. The disclosure may include leverage buyout transactions (as applicable).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
-Section 50
-Paragraph 5
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 4
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 805
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Reference 4: http://www.xbrl.org/2003/role/presentationRef
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Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
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-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=73530397&loc=d3e4845-128472

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=65885119&loc=d3e1524-128463

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e7000-128479

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=73530397&loc=d3e4922-128472

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-Publisher FASB
-Name Accounting Standards Codification
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Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=73530397&loc=SL65897772-128472

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
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Reference 15: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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+ Details

Other Receivables and Current Assets

12 Months Ended

Dec. 31, 2016

Prepaid Expense and Other Assets, Current [Abstract]

Other Receivables and Current Assets

The Company's other receivables and current assets comprise the following balances:



	December 31,
(in thousands)	2016		2015
Receivables related to unrecognized revenue	$	199,119	$	170,186
Income taxes receivable, including overpayments and refunds	15,718		7,877
Prepaid expenses and other current assets	24,512		22,170
Total other receivables and current assets	$	239,349	$	200,233

Receivables for unrecognized revenue represent the current portion of billings made for annual lease licenses and software maintenance that have not yet been recognized as revenue.

Property and Equipment

12 Months Ended

Dec. 31, 2016

Property, Plant and Equipment [Abstract]

Property and Equipment

Property and equipment consists of the following:



		December 31,
(in thousands)	Estimated Useful Lives	2016			2015
Equipment	1-10 years	$	78,614		$	78,932
Computer software	1-5 years	30,867			33,710
Buildings	10-40 years	25,472			25,041
Leasehold improvements	1-15 years	11,571			12,621
Furniture	1-13 years	8,618			8,601
Land		1,759			1,759
Property and equipment, gross		156,901			160,664
Less: Accumulated depreciation		(102,224		)	(98,740		)
Property and equipment, net		$	54,677		$	61,924

Depreciation expense related to property and equipment was $18.7 million, $19.5 million and $20.9 million for the years ended December 31, 2016, 2015 and 2014, respectively.

Goodwill and Intangible Assets

12 Months Ended

Dec. 31, 2016

Goodwill and Intangible Assets Disclosure [Abstract]

Goodwill and Intangible Assets

Goodwill represents the excess of the fair value of the consideration transferred over the value of net tangible and identifiable intangible assets of acquired businesses. Identifiable intangible assets acquired in business combinations are recorded based on their fair values on the date of acquisition.

During the first quarter of 2016, 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, 2016. No other events or circumstances changed during the twelve months ended December 31, 2016 that would indicate that the fair values of the Company's reporting unit and indefinite lived intangible asset are below their carrying values.

The Company's intangible assets and estimated useful lives are classified as follows:



	December 31, 2016					December 31, 2015
(in thousands)	Gross Carrying Amount		Accumulated Amortization			Gross Carrying Amount		Accumulated Amortization
Finite-lived intangible assets:
Developed software and core technologies (3 – 11 years)	$	338,594	$	(275,130	)	$	336,262	$	(251,201	)
Customer lists and contract backlog (5 – 15 years)	159,549		(88,414		)	159,885		(76,160		)
Trade names (2 – 10 years)	127,952		(90,289		)	127,903		(76,493		)
Total	$	626,095	$	(453,833	)	$	624,050	$	(403,854	)
Indefinite-lived intangible assets:
Trade names	$	357				$	357

Amortization expense for the intangible assets reflected above was $50.8 million, $58.1 million and $61.0 million for the years ended December 31, 2016, 2015 and 2014, respectively.

As of December 31, 2016, estimated future amortization expense for the intangible assets reflected above is as follows:



(in thousands)
2017	$	47,937
2018	34,643
2019	21,332
2020	20,325
2021	16,199
Thereafter	31,826
Total intangible assets subject to amortization, net	172,262
Indefinite-lived trade name	357
Other intangible assets, net	$	172,619

The changes in goodwill during the years ended December 31, 2016 and 2015 are as follows:



(in thousands)	2016			2015
Beginning balance - January 1	$	1,332,348		$	1,312,182
Acquisitions	6,184			28,561
Adjustments⁽¹⁾	(1		)	(4,573		)
Currency translation	(1,316		)	(3,822		)
Ending balance - December 31	$	1,337,215		$	1,332,348

⁽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.

- Definition

The entire disclosure for the aggregate amount of goodwill and a description of intangible assets, which may include (a) for amortizable intangible assets (also referred to as finite-lived intangible assets), the carrying amount, the amount of any significant residual value, and the weighted-average amortization period, (b) for intangible assets not subject to amortization (also referred to as indefinite-lived intangible assets), the carrying amount, and (c) the amount of research and development assets acquired and written off in the period, including the line item in the income statement in which the amounts written off are aggregated, if not readily apparent from the income statement. Also discloses (a) for amortizable intangibles assets in total and by major class, the gross carrying amount and accumulated amortization, the total amortization expense for the period, and the estimated aggregate amortization expense for each of the five succeeding fiscal years, (b) for intangible assets not subject to amortization the carrying amount in total and by major class, and (c) for goodwill, in total and for each reportable segment, the changes in the carrying amount of goodwill during the period (including the aggregate amount of goodwill acquired, the aggregate amount of impairment losses recognized, and the amount of goodwill included in the gain (loss) on disposal of a reporting unit). If any part of goodwill has not been allocated to a reportable segment, discloses the unallocated amount and the reasons for not allocating. For each impairment loss recognized related to an intangible asset (excluding goodwill), discloses: (a) a description of the impaired intangible asset and the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method for determining fair value, (c) the caption in the income statement or the statement of activities in which the impairment loss is aggregated, and (d) the segment in which the impaired intangible asset is reported. For each goodwill impairment loss recognized, discloses: (a) a description of the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method of determining the fair value of the associated reporting unit, and (c) if a recognized impairment loss is an estimate not finalized and the reasons why the estimate is not final. May also disclose the nature and amount of any significant adjustments made to a previous estimate of an impairment loss.

+ References + Details

Fair Value Measurement

12 Months Ended

Dec. 31, 2016

Fair Value Disclosures [Abstract]

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 and liabilities carried at fair value and measured on a recurring basis:



			Fair Value Measurements at Reporting Date Using:
(in thousands)	December 31, 2016		Quoted Prices in Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets
Cash equivalents	$	333,975	$	333,975	$	—	$	—
Short-term investments	$	381	$	—	$	381	$	—
Deferred compensation plan investments	$	459	$	459	$	—	$	—



				Fair Value Measurements at Reporting Date Using:
(in thousands)	December 31, 2015			Quoted Prices in Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets
Cash equivalents	$	356,924		$	356,924	$	—	$	—
Short-term investments	$	446		$	—	$	446	$	—
Liabilities
Contingent consideration	$	(1,376	)	$	—	$	—	$	(1,376	)

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 original maturities ranging from three months to one year.

The deferred compensation plan investments in the preceding table represent trading securities held in a rabbi trust for the benefit of the non-affiliate Independent Directors. These securities consist of mutual funds traded in an active market with quoted prices. As a result, the plan assets were classified as Level 1 in the fair value hierarchy. The plan assets are recorded within other long-term assets on the Company's consolidated balance sheet.

The contingent consideration in the table above represents the final payment related to the 2013 acquisition of EVEN - Evolutionary Engineering AG ("EVEN"). The net present value calculation for the contingent consideration, which was paid during the quarter ended March 31, 2016, included significant unobservable inputs as of December 31, 2015 in the assumption that the remaining payment would be made, and, therefore, the liability was classified as Level 3 in the fair value hierarchy. The liability was recorded within other accrued expenses and liabilities on the Company's consolidated balance sheet.

The following table presents the changes during the years ended December 31, 2016 and 2015 in the Company's Level 3 liability for contingent consideration that is measured at fair value on a recurring basis:



	Fair Value Measurement Using Significant Unobservable Inputs
(in thousands)	Contingent Consideration
Balance as of January 1, 2015	$	2,621
Contingent payments	(1,456		)
Interest expense and foreign exchange activity included in earnings	211
Balance as of December 31, 2015	$	1,376
Contingent payments	(1,448		)
Interest expense and foreign exchange activity included in earnings	72
Balance as of December 31, 2016	$	—

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

12 Months Ended

Dec. 31, 2016

Income Tax Disclosure [Abstract]

Income Taxes

Income before income taxes includes the following components:



	Year Ended December 31,
(in thousands)	2016		2015		2014
Domestic	$	340,251	$	325,097	$	291,042
Foreign	40,064		31,668		57,097
Total	$	380,315	$	356,765	$	348,139

The provision for income taxes is composed of the following:



	Year Ended December 31,
(in thousands)	2016			2015			2014
Current:
Federal	$	99,783		$	93,853		$	80,620
State	8,338			7,733			7,192
Foreign	17,479			17,854			24,495
Deferred:
Federal	(13,368		)	(14,472		)	(18,536		)
State	(1,036		)	(1,987		)	(1,915		)
Foreign	3,483			1,263			1,593
Total	$	114,679		$	104,244		$	93,449

The reconciliation of the U.S. federal statutory tax rate to the consolidated effective tax rate is as follows:



	Year Ended December 31,
	2016		2015		2014
Federal statutory tax rate	35.0	%	35.0	%	35.0	%
State income taxes, net of federal benefit	1.6		1.1		1.2
Uncertain tax positions	(0.2	)	(0.4	)	(0.9	)
Research and development credits	(1.0	)	(1.1	)	(1.1	)
Benefit from restructuring activities	(2.2	)	(2.7	)	(4.1	)
Domestic production activity benefit	(3.7	)	(3.1	)	(3.5	)
Other	0.7		0.4		0.2
	30.2	%	29.2	%	26.8	%

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. The Company has not made a provision for U.S. taxes on approximately $199 million, representing the excess of the amount for financial reporting over the tax bases of investments in foreign subsidiaries that are essentially permanent in duration. Generally, such amounts become subject to U.S. taxation upon the remittance of dividends and under certain other circumstances. The residual U.S. tax cost associated with this difference is estimated to be $35 million.

The components of deferred tax assets and liabilities are as follows:



	December 31,
(in thousands)	2016			2015
Deferred tax assets:
Net operating loss carryforwards	$	32,969		$	40,939
Stock-based compensation	23,652			23,258
Employee benefits	17,187			17,044
Uncertain tax positions	11,562			10,233
Deferred revenue	6,382			8,603
Research and development credits	3,889			3,562
Allowance for doubtful accounts	2,078			1,888
Other	3,163			3,240
Valuation allowance	(1,625		)	(603		)
	99,257			108,164
Deferred tax liabilities:
Other intangible assets	(56,195		)	(73,933		)
Property and equipment	(2,994		)	(3,426		)
	(59,189		)	(77,359		)
Net deferred tax assets	$	40,068		$	30,805

The Company excluded from the above table a $13.2 million deferred tax asset associated with foreign net operating loss carryforwards and a corresponding $13.2 million valuation allowance in a jurisdiction where the Company determined utilization is remote.

The net increase in the gross valuation allowance was $1.0 million. This increase was primarily due to a change in circumstances related to the ability to utilize a net operating loss in a foreign jurisdiction. As of each reporting date, management considers new evidence, both positive and negative, that could affect the future realization of deferred tax assets. If management determines it is more likely than not that an asset, or a portion of an asset, will not be realized, a valuation allowance is recorded.

As of December 31, 2016, the Company had federal net operating loss carryforwards of $28.7 million. These losses expire between 2020 - 2034, and are subject to limitations on their utilization. Deferred tax assets of $1.2 million have been recorded for state operating loss carryforwards. These losses expire between 2017 - 2035, and are subject to limitations on their utilization. The Company had total foreign net operating loss carryforwards of $76.9 million, of which $28.2 million are not currently subject to expiration dates. The remainder, $48.7 million, expires between 2019 - 2025. The Company had tax credit carryforwards of $5.2 million, of which $3.0 million are subject to limitations on their utilization. Approximately $0.9 million of these tax credit carryforwards are not currently subject to expiration dates. The remainder, $4.3 million, expires in various years between 2017 - 2036.

The following is a reconciliation of the total amounts of unrecognized tax benefits:



	Year Ended December 31,
(in thousands)	2016			2015			2014
Unrecognized tax benefit as of January 1	$	16,067		$	16,342		$	19,590
Gross increases—tax positions in prior period	983			64			488
Gross decreases—tax positions in prior period	(2,502		)	(850		)	(3,715		)
Gross increases—tax positions in current period	2,725			4,064			2,513
Reductions due to a lapse of the applicable statute of limitations	(927		)	(2,808		)	(1,924		)
Changes due to currency fluctuation	(348		)	(653		)	(610		)
Settlements	(789		)	(92		)	—
Unrecognized tax benefit as of December 31	$	15,209		$	16,067		$	16,342

The Company believes that it is reasonably possible that approximately $0.1 million of uncertain tax positions may be resolved within the next twelve months as a result of settlement with a taxing authority or a lapse of the statute of limitations. Of the total unrecognized tax benefit as of December 31, 2016, $9.2 million would affect the effective tax rate, if recognized.

The Company recognizes interest and penalties related to income taxes as income tax expense. During the year ended December 31, 2016, the Company recorded $0.8 million of penalty expense and $0.1 million of interest benefit. As of December 31, 2016, the Company accrued a liability for penalties of $2.7 million and interest of $2.8 million. As of December 31, 2015, the Company accrued a liability for penalties of $1.9 million and interest of $2.7 million.

The Company is subject to taxation in the U.S. and various states and foreign jurisdictions. In the U.S., the Company's only major tax jurisdiction, the 2013 - 2016 tax years are open to examination by the Internal Revenue Service.

Pension And Profit-Sharing Plans	12 Months Ended
Pension And Profit-Sharing Plans	Dec. 31, 2016
Compensation and Retirement Disclosure [Abstract]
Pension And Profit-Sharing Plans	Pension and Profit-Sharing Plans The Company has a 401(k)/profit-sharing plan for all qualifying salaried domestic employees that permits participants to make contributions by salary reduction pursuant to Section 401(k) of the Internal Revenue Code. The Company makes matching contributions on behalf of each eligible participant in an amount equal to 100% of the first 3% and an additional 25% of the next 5%, for a maximum total of 4.25% of the employee's compensation. The Company may make a discretionary contribution based on the participant's eligible compensation, provided the employee is employed at the end of the year and has worked at least 1,000 hours. The Company also maintains various defined contribution and defined benefit pension arrangements for its international employees. The Company funds the foreign defined benefit and contribution plans based on the minimum required deposits according to the local statutory requirements. The unfunded portion of the defined benefit obligation for each plan is accrued in other long-term liabilities. Expenses related to the Company's retirement programs were $9.1 million in 2016, $8.4 million in 2015 and $8.9 million in 2014.

Non-Compete and Employment Agreements	12 Months Ended
Non-Compete and Employment Agreements	Dec. 31, 2016
Non-Compete and Employment Agreements [Abstract]
Non-Compete and Employment Agreements	Non-Compete and Employment Agreements Employees of the Company have signed agreements under which they have agreed not to disclose trade secrets or confidential information that, where legally permitted, restrict engagement in or connection with any business that is competitive with the Company anywhere in the world while employed by the Company (and, in some cases, for specified periods thereafter), and that any products or technology created by them during their term of employment are the property of the Company. In addition, the Company requires all channel partners to enter into agreements not to disclose the Company's trade secrets and other proprietary information. The Company has an employment agreement with the Chief Executive Officer. This agreement provides for, among other things, in the case of termination for reasons other than death, disability or cause and subject to non-compete and non-solicit clauses, minimum severance payments equal to two times his base salary and target bonus paid out over two years from the date of termination and two years of health care coverage from the date of termination. The Chief Executive Officer is subject to a two-year restriction on competition and solicitation following termination of employment under the circumstances described in the contract. The Company has a transition agreement with its Chairman of the Board. This agreement provides for, among other things, that the Chairman of the Board shall be employed by the Company until April 30, 2019 unless terminated earlier in accordance with the terms of the agreement. The Chairman of the Board shall receive salary paid in bi-monthly installments as specified in the transition agreement and restricted stock units vesting in part in February 2018 and the remainder at the end of the transition agreement, subject to the Chairman of the Board's continued employment, in accordance with the terms of the transition agreement. The Chairman of the Board will not be entitled to bonus payments during his employment pursuant to the transition agreement, but he will be eligible to participate in all of the Company’s benefit plans subject to the terms of such plans. The transition agreement provides for an additional payment (less salary received and equity calculations as set forth in the transition agreement) in the event that the Chairman of the Board's employment is terminated without cause prior to April 30, 2019. The Company also has employment agreements with several other employees, primarily in foreign jurisdictions. The terms of these employment agreements generally include annual compensation, severance payment provisions and non-compete clauses.

Stock-Based Compensation

12 Months Ended

Dec. 31, 2016

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Stock-Based Compensation

The Company has a stock option and grant plan—the Fifth Amended and Restated 1996 Stock Option and Grant Plan ("Stock Plan"). The Stock Plan, as amended, authorizes the grant of up to 39.8 million shares of the Company's common stock in the form of: (i) incentive stock options ("ISOs"), (ii) nonqualified stock options, (iii) common stock with or without vesting or other restrictions, (iv) common stock upon the attainment of specified performance goals, (v) restricted stock awards, (vi) the right to receive cash dividends with the holders of the common stock as if the recipient held a specified number of shares of the common stock, (vii) deferred stock awards, (viii) restricted stock unit awards, (ix) stock appreciation rights and (x) cash-based awards.

The Stock Plan provides that: (i) the exercise price of an ISO must be no less than the fair value of the stock at the date of grant and (ii) the exercise price of an ISO held by an optionee who possesses more than 10% of the total combined voting power of all classes of stock must be no less than 110% of the fair market value of the stock at the time of grant. The Compensation Committee of the Board of Directors has the authority to set expiration dates no later than ten years from the date of grant (or five years for an optionee who meets the 10% criterion), payment terms, and other provisions for each grant. The majority of options granted have a four-year vesting period. Shares associated with unexercised options or reacquired shares of common stock (except those shares withheld as a result of tax withholding or net issuance) become available for option grants and common stock issuances under the Stock Plan. The Compensation Committee of the Board of Directors may, at its sole discretion, accelerate or extend the date or dates on which all or any particular award or awards granted under the Stock Plan may vest or be exercised.

In the event of a "sale event," defined in the Stock Plan as a "Transaction," all outstanding awards will be assumed or continued by the successor entity, with appropriate adjustment in the awards to reflect the transaction. In such event, except as the Compensation Committee may otherwise specify with respect to particular awards in the award agreements, if the service relationship of the holder of an award is terminated without cause within 18 months after the sale event, then all awards held by such holder will become fully vested and exercisable at that time. If there is a sale event in which the successor entity refuses to assume or continue outstanding awards, then subject to the consummation of the sale event, all awards with time-based vesting conditions will become fully vested and exercisable at the effective time of the sale event and all awards with performance-based vesting conditions may become vested and exercisable in accordance with the award agreements at the discretion of the Compensation Committee. If awards are not assumed or continued after a sale event, then all such awards will terminate at the time of the sale event. In the event of the termination of stock options or stock appreciation rights in connection with a sale event, the Compensation Committee may either make or provide for a cash payment to the holders of such awards equal to the difference between the per share transaction consideration and the exercise price of such awards or permit each holder to have at least a 15-day period to exercise such awards prior to their termination.

The Company currently issues shares related to exercised stock options or vested awards from its existing pool of treasury shares and has no specific policy to repurchase treasury shares as stock options are exercised or as awards vest. If the treasury pool is depleted, the Company will issue new shares.

Total stock-based compensation expense recognized for the years ended December 31, 2016, 2015 and 2014 is as follows:



	Year Ended December 31,
(in thousands, except per share amounts)	2016			2015			2014
Cost of sales:
Software licenses	$	701		$	745		$	1,776
Maintenance and service	1,578			1,868			2,035
Operating expenses:
Selling, general and administrative	15,990			17,153			17,073
Research and development	15,078			14,185			15,977
Stock-based compensation expense before taxes	33,347			33,951			36,861
Related income tax benefits	(10,538		)	(11,656		)	(10,927		)
Stock-based compensation expense, net of taxes	$	22,809		$	22,295		$	25,934
Net impact on earnings per share:
Basic earnings per share	$	(0.26	)	$	(0.25	)	$	(0.28	)
Diluted earnings per share	$	(0.26	)	$	(0.24	)	$	(0.28	)

Information regarding stock option transactions is summarized below:



	Year Ended December 31,
	2016				2015				2014
(options in thousands)	Options		Weighted- Average Exercise Price		Options		Weighted- Average Exercise Price		Options		Weighted- Average Exercise Price
Outstanding, beginning of year	3,986		$	51.07	4,932		$	48.76	6,166		$	44.77
Granted	260		$	94.38	57		$	88.10	150		$	81.09
Issued pursuant to acquisitions	—		$	—	8		$	12.26	21		$	23.26
Exercised	(1,082	)	$	45.57	(975	)	$	40.52	(1,266	)	$	31.36
Forfeited	(28	)	$	72.07	(36	)	$	70.15	(139	)	$	61.11
Outstanding, end of year	3,136		$	56.37	3,986		$	51.07	4,932		$	48.76
Vested and Exercisable, end of year	2,762		$	51.80	3,539		$	48.29	3,958		$	44.22



	2016		2015		2014
Weighted-Average Remaining Contractual Term (in years)
Outstanding	4.62		4.85		5.53
Vested and Exercisable	4.04		4.53		5.00
Aggregate Intrinsic Value (in thousands)
Outstanding	$	113,822	$	165,131	$	163,932
Vested and Exercisable	$	112,379	$	156,487	$	149,536

Historical and future expected forfeitures have not been significant and, as a result, the outstanding option amounts reflected in the tables above approximate the options expected to vest.

The fair value of each option grant is estimated on the date of grant, or date of acquisition for options issued in a business combination, using the Black-Scholes option pricing model, which was developed for use in estimating the fair value of traded options that have no vesting restrictions and are fully transferable. The Company's options have characteristics significantly different from those of traded options, and changes in input assumptions can materially affect the fair value estimates. The interest rates used were determined by using the five-year Treasury Note yield at the date of grant or date of acquisition for options issued in a business combination. The volatility was determined based on the historic volatility of the Company's stock during the preceding six years for 2016, 2015 and 2014.

The table below presents the weighted average input assumptions used and resulting fair values for options granted or issued in business combinations during each respective year:



	Year Ended December 31,
	2016	2015	2014
Risk-free interest rate	1.19% to 1.93%	1.18% to 1.65%	1.49% to 1.76%
Expected dividend yield	—%	—%	—%
Expected volatility	24%	25%	35%
Expected term	5.7 years	5.6 years	5.7 years
Weighted-average fair value per share	$23.96	$30.83	$32.26

As stock-based compensation expense recognized in the consolidated statements of income is based on awards ultimately expected to vest, it must be reduced for estimated forfeitures. Forfeitures are estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. The effect of pre-vesting forfeitures on the Company's recorded expense has historically been negligible due to the relatively low turnover of stock option holders.

The Company's determination of fair value of share-based payment awards on the date of grant using an option pricing model is affected by the Company's stock price as well as assumptions regarding a number of variables. The total estimated grant-date fair values of stock options that vested during the years ended December 31, 2016, 2015 and 2014 were $7.4 million, $12.3 million and $19.5 million, respectively. As of December 31, 2016, total unrecognized estimated compensation cost related to unvested stock options granted prior to that date was $8.2 million, which is expected to be recognized over a weighted-average period of 2.1 years. The total intrinsic values of stock options exercised during the years ended December 31, 2016, 2015 and 2014 were $49.8 million, $47.1 million and $60.6 million, respectively. As of December 31, 2016, 0.4 million unvested options with an aggregate intrinsic value of $1.4 million are expected to vest and have a weighted-average exercise price of $90.12 and a weighted-average remaining contractual term of 8.9 years. The Company recorded cash received from the exercise of stock options of $49.3 million and tax benefits related to stock activity of $18.6 million for the year ended December 31, 2016.

Information regarding stock options outstanding as of December 31, 2016 is summarized below:



(options in thousands)	Options Outstanding				Options Exercisable
Range of Exercise Prices	Options	Weighted- Average Remaining Contractual Life (years)	Weighted- Average Exercise Price		Options	Weighted- Average Exercise Price
$5.91 - $40.89	874	2.35	$	34.25	868	$	34.39
$41.33 - $58.67	1,175	4.25	$	54.02	1,175	$	54.02
$61.68 - $69.70	641	5.71	$	67.38	641	$	67.38
$73.45 - $95.09	446	8.47	$	90.11	78	$	83.78

Under the terms of the ANSYS, Inc. Long-Term Incentive Plan, the Company issues various restricted stock awards, which may have a market condition, an operating performance condition or a service condition, or any combination of the three. The Company granted 35,000, 34,450 and 47,000 performance-based restricted stock units with a market condition in 2016, 2015 and 2014, respectively. The percentage of the award that vests is based on the Company's performance as measured by total shareholder return relative to the appreciation of a specified stock index over the measurement period, subject to each participant's continued employment with the Company through the conclusion of the measurement period. As of December 31, 2016, 5,973 units of the total 2014 awards granted were earned and will be issued in 2017. The measurement periods for the restricted stock units granted pursuant to the Long-Term Incentive Plan are one-, two- and three-year periods beginning January 1 of the year of the grant. Each restricted stock unit relates to one share of the Company's common stock. The weighted-average fair value of each restricted stock unit granted in 2016, 2015 and 2014 was estimated on the grant date to be $78.71, $81.61 and $65.94, respectively. The fair value of the restricted stock units was estimated using a Monte Carlo simulation model. The determination of the fair value of the awards was affected by the grant date and a number of variables, each of which has been identified in the chart below. Share-based compensation expense based on the fair value of the award is being recorded from the grant date through the conclusion of the three-year measurement period. Total compensation expense associated with the market condition awards recorded for the years ended December 31, 2016, 2015 and 2014 was $2.2 million, $3.1 million and $2.5 million, respectively.



	Year Ended December 31,
Assumptions used in Monte Carlo lattice pricing model	2016	2015	2014
Risk-free interest rate	1.0%	1.1%	0.7%
Expected dividend yield	—%	—%	—%
Expected volatility—ANSYS stock price	21%	23%	25%
Expected volatility—NASDAQ Composite Index	16%	14%	15%
Expected term	2.8 years	2.8 years	2.8 years
Correlation factor	0.65	0.60	0.70

The Company issued 35,000, 115,485 and 39,900 performance-based restricted stock awards during 2016, 2015 and 2014, respectively. Of the cumulative performance-based restricted stock awards issued, defined operating metrics were assigned to 63,462, 51,795 and 20,667 awards with grant-date fair values of $84.61, $86.38 and $81.52 during 2016, 2015 and 2014, respectively. The grant-date fair value of the awards is being recorded from the grant date through the conclusion of the measurement period associated with each operating metric based on management's estimates concerning the probability of vesting. As of December 31, 2016, 7,625 units of the total 2014 awards granted were earned and will be issued in 2017. Total compensation expense associated with the awards recorded for the years ended December 31, 2016, 2015 and 2014 was $0.4 million, $0.4 million and $0.1 million, respectively.

In addition, in 2016, 2015 and 2014, the Company granted restricted stock units of 488,622, 344,500 and 364,150, respectively, that will vest over a three- or four-year period with weighted-average grant-date fair values of $88.51, $86.34 and $82.13, respectively. During 2016 and 2015, 162,019 and 85,713 shares vested and were released, respectively. As of December 31, 2016, 2015 and 2014, 838,327, 571,462 and 344,750 units were outstanding, respectively. Total compensation expense is being recorded over the service period and was $19.1 million, $12.5 million and $5.8 million for the years ended December 31, 2016, 2015 and 2014, respectively.

In conjunction with a 2015 acquisition, ANSYS issued 68,451 shares of replacement restricted stock with a weighted-average grant-date fair value of $90.48. Of the $6.2 million grant-date fair value, $3.5 million, related to partially vested awards, was recorded as non-cash purchase price consideration. The remaining fair value will be recognized as stock compensation expense through the conclusion of the service period. During the years ended December 31, 2016 and 2015, the Company recorded $1.2 million and $0.6 million, respectively, of stock compensation expense related to these awards.

In conjunction with a 2011 acquisition, the Company granted performance-based restricted stock awards. Vesting was determined based on the achievements of certain revenue and operating income targets of the entity post-acquisition. Total compensation expense associated with the awards recorded for the year ended December 31, 2014 was $4.7 million.

The Company has granted deferred stock awards to non-affiliate Independent Directors, which are rights to receive shares of common stock upon termination of service as a Director. In 2015 and prior, the deferred stock awards were granted quarterly in arrears and vested immediately upon grant. Associated with these awards, the Company established a non-qualified 409(a) deferred compensation plan with assets held under a rabbi trust to provide Directors an opportunity to diversify their vested awards. During open trading windows and at their elective option, the Directors may convert their Company shares into a variety of non-Company-stock investment options in order to diversify their holdings. As of December 31, 2016, 5,000 shares have been diversified and 184,099 undiversified deferred stock awards have vested with the underlying shares remaining unissued until the service termination of the respective Director owners. In May 2016, the Company granted 38,400 deferred stock awards which will vest in full on the one-year anniversary of the grant. Total compensation expense associated with the awards recorded for the years ended December 31, 2016, 2015 and 2014 was $1.9 million, $4.0 million and $3.5 million, respectively.

- Definition

The entire disclosure for compensation-related costs for equity-based compensation, which may include disclosure of policies, compensation plan details, allocation of equity compensation, incentive distributions, equity-based arrangements to obtain goods and services, deferred compensation arrangements, employee stock ownership plan details and employee stock purchase plan details.

+ References + Details

Stock Repurchase Program

12 Months Ended

Dec. 31, 2016

Class of Stock Disclosures [Abstract]

Stock Repurchase Program

Under the Company's stock repurchase program, the Company repurchased shares as follows:



	Year Ended December 31,
(in thousands, except per share data)	2016		2015		2014
Number of shares repurchased	3,700		3,833		2,977
Average price paid per share	$	90.90	$	88.16	$	78.54
Total cost	$	336,335	$	337,910	$	233,793

In February 2017, 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 December 31, 2016, 1.3 million shares remained available for repurchase under the program.

Employee Stock Purchase Plan	12 Months Ended
Employee Stock Purchase Plan	Dec. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Employee Stock Purchase Plan	Employee Stock Purchase Plan The Company's 1996 Employee Stock Purchase Plan (the “Purchase Plan”) was adopted by the Board of Directors on April 19, 1996 and was subsequently approved by the Company's stockholders. The stockholders approved an amendment to the Purchase Plan in May 2016 to increase the number of shares available for offerings to 1.8 million shares. The Purchase Plan is administered by the Compensation Committee. Offerings under the Purchase Plan commence on each February 1 and August 1, and have a duration of six months. An employee who owns or is deemed to own shares of stock representing in excess of 5% of the combined voting power of all classes of stock of the Company may not participate in the Purchase Plan. During each offering, an eligible employee may purchase shares under the Purchase Plan by authorizing payroll deductions of up to 10% of his or her cash compensation during the offering period. The maximum number of shares that may be purchased by any participating employee during any offering period is limited to 3,840 shares (as adjusted by the Compensation Committee from time to time). Unless the employee has previously withdrawn from the offering, his or her accumulated payroll deductions will be used to purchase common stock on the last business day of the period at a price equal to 90% of the fair market value of the common stock on the first or last day of the offering period, whichever is lower. Under applicable tax rules, an employee may not accrue the right to purchase more than $25,000 of common stock, based on the grant-date fair value, in any calendar year. As of December 31, 2016, 1.4 million shares of common stock had been issued under the Purchase Plan. The total compensation expense recorded under the Purchase Plan during the years ended December 31, 2016, 2015 and 2014 was $1.2 million, $1.0 million and $0.9 million, respectively.

Leases

12 Months Ended

Dec. 31, 2016

Leases [Abstract]

Leases

Office Space

The Company's executive offices and those related to certain domestic product development, marketing, production and administration are located in a 186,000 square foot office facility in Canonsburg, Pennsylvania. The lease was effective as of September 14, 2012, but because the leased premises were under construction, the Company was not obligated to pay rent until three months following the date that the leased premises were delivered to ANSYS, which occurred on October 1, 2014. The term of the lease is 183 months, beginning on October 1, 2014. Absent the exercise of options in the lease for additional rentable space or early lease termination, the Company's base rent (inclusive of property taxes and certain operating expenses) will be $4.3 million per annum for the first five years of the lease term, $4.5 million per annum for years six through ten and $4.7 million per annum for years eleven through fifteen. The Company incurred $4.4 million, $4.4 million and $0.8 million in lease expense related to this facility during the years ended December 31, 2016, 2015 and 2014, respectively.

The Company's corporate headquarters was previously located in a separate office facility, also in Canonsburg, Pennsylvania. The Company occupied this space until November 2014, and the lease term expired on December 31, 2014. Lease expense related to this facility was $1.4 million during the year ended December 31, 2014.

The Company has entered into various other noncancellable operating leases for office space.

Office space lease expense totaled $16.9 million, $16.5 million and $15.8 million for the years ended December 31, 2016, 2015 and 2014, respectively. Future minimum lease payments, including termination fees, under noncancellable operating leases for office space in effect at December 31, 2016 are as follows:



(in thousands)
2017	$	12,516
2018	9,901
2019	9,178
2020	6,961
2021	6,132
Thereafter	21,204
Total	$	65,892

Royalty Agreements	12 Months Ended
Royalty Agreements	Dec. 31, 2016
Royalty Agreements [Abstract]
Royalty Agreements	Royalty Agreements The Company has entered into various renewable, nonexclusive license agreements under which the Company has been granted access to the licensor's technology and the right to sell the technology in the Company's product line. Royalties are payable to developers of the software at various rates and amounts, which generally are based upon unit sales, revenue or flat fees. Royalty fees are reported in cost of goods sold and were $13.1 million, $11.8 million and $11.5 million for the years ended December 31, 2016, 2015 and 2014, respectively.

Geographic Information (Notes)

12 Months Ended

Dec. 31, 2016

Segments, Geographical Areas [Abstract]

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:



	Year Ended December 31,
(in thousands)	2016		2015		2014
United States	$	367,937	$	354,433	$	320,327
Japan	120,160		104,299		108,757
Germany	99,814		94,546		99,714
South Korea	56,790		55,142		55,606
France	49,294		49,444		58,785
Canada	13,284		13,314		14,034
Other European	139,813		145,985		159,011
Other international	141,373		125,590		119,787
Total revenue	$	988,465	$	942,753	$	936,021

Property and equipment by geographic area is as follows:



	December 31,
(in thousands)	2016		2015
United States	$	43,810	$	47,971
Europe	4,753		6,808
India	3,033		3,286
Other international	3,081		3,859
Total property and equipment, net	$	54,677	$	61,924

Unconditional Purchase Obligations

12 Months Ended

Dec. 31, 2016

Unconditional Purchase Obligations (Excluding Capital Stock Redemptions) [Abstract]

Unconditional Purchase Obligations

The Company has entered into various unconditional purchase obligations which primarily include software licenses and long-term purchase contracts for network, communication and office maintenance services. The Company expended $7.2 million, $5.3 million and $2.9 million related to unconditional purchase obligations that existed as of the beginning of each year for the years ended December 31, 2016, 2015 and 2014, respectively. Future expenditures under unconditional purchase obligations in effect as of December 31, 2016 are as follows:



(in thousands)
2017	$	14,134
2018	10,288
2019	9,724
2020	2,617
2021	652
Total	$	37,415

Restructuring (Notes)	12 Months Ended
Restructuring (Notes)	Dec. 31, 2016
Restructuring and Related Activities [Abstract]
Restructuring	Restructuring During the fourth quarter of 2016, the Company initiated workforce realignment activities. The Company incurred $3.4 million in restructuring charges, or $2.4 million net of tax, during the year ended December 31, 2016. The Company expects to incur additional charges of $10 million - $15 million, or $7 million - $10 million net of tax, primarily during the first quarter of 2017.

Employment-Related Settlement (Notes)	12 Months Ended
Employment-Related Settlement (Notes)	Dec. 31, 2016
Other Liabilities [Abstract]
Other Liabilities Disclosure	Employment-Related Settlement On February 15, 2017, the Company entered into an employment-related settlement agreement. In connection with the settlement agreement, the Company will make a lump-sum payment of $4.7 million. The charges related to this agreement are included in selling, general and administrative expense in the 2016 consolidated statement of income. As part of the settlement agreement, all the claims initiated against the Company will be withdrawn and a general release of all claims in favor of the Company and all of its related entities was executed.

Contingencies and Commitments (Notes)	12 Months Ended
Contingencies and Commitments (Notes)	Dec. 31, 2016
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, including those related to the service tax audit case, of approximately $7 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) has passed a favorable ruling to Microsoft. The Company can provide no assurances on whether the Microsoft case’s favorable ruling will be challenged in higher courts or 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. A French subsidiary of the Company received notice that the French taxing authority rejected the Company's 2012 research and development credit. The Company has contested the decision. However, if the Company does not receive a favorable outcome, it could incur charges of approximately $0.8 million. In addition, an unfavorable outcome could result in the authorities reviewing or rejecting $3.8 million of similar research and development credits for 2013 through the current year that are currently reflected as an asset. The Company can provide no assurances on the timing or outcome of this matter. 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 December 31, 2016. 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.

Schedule II - Valuation and Qualifying Accounts (Notes)

12 Months Ended

Dec. 31, 2016

Valuation and Qualifying Accounts [Abstract]

Valuation and Qualifying Accounts

ANSYS, INC. AND SUBSIDIARIES

Valuation and Qualifying Accounts



(in thousands) Description	Balance at Beginning of Year		Additions: Charges to Costs and Expenses		Deductions: Returns and Write-Offs		Balance at End of Year
Year ended December 31, 2016 Allowance for doubtful accounts	$	5,200	$	2,009	$	1,509	$	5,700
Year ended December 31, 2015 Allowance for doubtful accounts	$	5,500	$	1,304	$	1,604	$	5,200
Year ended December 31, 2014 Allowance for doubtful accounts	$	5,700	$	2,104	$	2,304	$	5,500

Summary Of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2016

Accounting Policies [Abstract]

Accounting Principles

The financial statements and accompanying notes are prepared in accordance with accounting principles generally accepted in the United States.

Principles Of Consolidation

The accompanying consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All intercompany accounts and transactions have been eliminated.

Use Of Estimates


•	Allowances for doubtful accounts receivable


•	Income tax accruals


•	Uncertain tax positions


•	Tax valuation reserves


•	Fair value of stock-based compensation


•	Contract revenue


•	Useful lives for depreciation and amortization


•	Valuations of goodwill and other intangible assets


•	Contingent consideration


•	Deferred compensation


•	Loss contingencies

Actual results could differ from these estimates. Changes in estimates are recorded in the results of operations in the period that the changes occur.

Revenue Recognition

Cash And Cash Equivalents



	December 31, 2016			December 31, 2015
(in thousands, except percentages)	Amount		% of Total	Amount		% of Total
Cash accounts	$	488,504	59.4	$	427,244	54.5
Money market funds	333,975		40.6	356,924		45.5
Total	$	822,479		$	784,168

The Company's money market fund balances are held in various funds of a single issuer.

Property And Equipment

Research And Development

Research and development costs, other than certain capitalized software development costs, are expensed as incurred.

Software Development Costs

Internally developed software costs required to be capitalized as defined by the accounting guidance are not material to the Company's consolidated financial statements.

Business Combinations

Goodwill And Other Intangible Assets

Concentrations Of Credit Risk



	Year Ended December 31,
(as a % of revenue)	2016		2015		2014
Revenue from channel partners	24	%	24	%	25	%
Largest channel partner	5	%	5	%	4	%
2^nd largest channel partner	2	%	2	%	2	%

No single customer accounted for more than 5% of the Company's revenue in 2016, 2015 or 2014.



	As of December 31,
(in thousands)	2016		2015
Cash and cash equivalents held domestically	$	593,348	$	539,031
Cash and cash equivalents held by foreign subsidiaries	229,131		245,137
Cash and cash equivalents held in excess of deposit insurance, foreign and domestic	805,374		763,400
Largest balance of cash and cash equivalents held with one financial institution, foreign and domestic	377,602		440,650

Allowance For Doubtful Accounts

Income Taxes

Foreign Currencies

Accumulated Other Comprehensive Loss

Accumulated other comprehensive loss is composed entirely of foreign currency translation adjustments.

Earnings Per Share

The details of basic and diluted EPS are as follows:



	Year Ended December 31,
(in thousands, except per share data)	2016		2015		2014
Net income	$	265,636	$	252,521	$	254,690
Weighted average shares outstanding – basic	87,227		89,561		92,067
Dilutive effect of stock plans	1,742		1,941		2,127
Weighted average shares outstanding – diluted	88,969		91,502		94,194
Basic earnings per share	$	3.05	$	2.82	$	2.77
Diluted earnings per share	$	2.99	$	2.76	$	2.70
Anti-dilutive options	260		206		718

Stock-Based Compensation

Fair Value Of Financial Instruments

New Accounting Guidance

Summary Of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2016

Summary Of Cash And Cash Equivalents

The Company's cash and cash equivalents balances comprise the following:



	December 31, 2016			December 31, 2015
(in thousands, except percentages)	Amount		% of Total	Amount		% of Total
Cash accounts	$	488,504	59.4	$	427,244	54.5
Money market funds	333,975		40.6	356,924		45.5
Total	$	822,479		$	784,168

Basic And Diluted Earnings Per Share

The details of basic and diluted EPS are as follows:



	Year Ended December 31,
(in thousands, except per share data)	2016		2015		2014
Net income	$	265,636	$	252,521	$	254,690
Weighted average shares outstanding – basic	87,227		89,561		92,067
Dilutive effect of stock plans	1,742		1,941		2,127
Weighted average shares outstanding – diluted	88,969		91,502		94,194
Basic earnings per share	$	3.05	$	2.82	$	2.77
Diluted earnings per share	$	2.99	$	2.76	$	2.70
Anti-dilutive options	260		206		718

Customer Concentration Risk [Member]

Schedule Of Risk Concentration

The following table outlines concentrations of risk with respect to the Company's revenue:



	Year Ended December 31,
(as a % of revenue)	2016		2015		2014
Revenue from channel partners	24	%	24	%	25	%
Largest channel partner	5	%	5	%	4	%
2^nd largest channel partner	2	%	2	%	2	%

Credit Concentration Risk [Member]

Schedule Of Risk Concentration

The following table outlines concentrations of risk with respect to the Company's cash and cash equivalents:



	As of December 31,
(in thousands)	2016		2015
Cash and cash equivalents held domestically	$	593,348	$	539,031
Cash and cash equivalents held by foreign subsidiaries	229,131		245,137
Cash and cash equivalents held in excess of deposit insurance, foreign and domestic	805,374		763,400
Largest balance of cash and cash equivalents held with one financial institution, foreign and domestic	377,602		440,650

Acquisitions (Tables) - SpaceClaim Corporation [Member]

12 Months Ended

Dec. 31, 2016

Business Acquisition [Line Items]

Fair Value of Consideration Transferred

Fair Value of Consideration Transferred:



(in thousands)
Cash	$	84,892
ANSYS replacement stock options	68
Total consideration transferred at fair value	$	84,960

Recognized Amounts of Identifiable Assets Acquired and Liabilities Assumed

Recognized Amounts of Identifiable Assets Acquired and Liabilities Assumed:



(in thousands)
Cash	$	723
Accounts receivable and other tangible assets	1,857
Developed technology (10-year life)	15,800
Customer relationships (6-year life)	9,400
Trade name (6-year life)	1,300
Contract backlog (6-year life)	550
Non-compete agreement (2-year life)	300
Net deferred tax assets	9,288
Accounts payable and other liabilities	(2,011		)
Deferred revenue	(700		)
Total identifiable net assets	$	36,507
Goodwill	$	48,453

Other Receivables and Current Assets (Tables)

12 Months Ended

Dec. 31, 2016

Prepaid Expense and Other Assets, Current [Abstract]

Schedule of Other Receivables and Current Assets

The Company's other receivables and current assets comprise the following balances:



	December 31,
(in thousands)	2016		2015
Receivables related to unrecognized revenue	$	199,119	$	170,186
Income taxes receivable, including overpayments and refunds	15,718		7,877
Prepaid expenses and other current assets	24,512		22,170
Total other receivables and current assets	$	239,349	$	200,233

Property and Equipment (Tables)

12 Months Ended

Dec. 31, 2016

Property, Plant and Equipment [Abstract]

Components Of Property and Equipment

Property and equipment consists of the following:



		December 31,
(in thousands)	Estimated Useful Lives	2016			2015
Equipment	1-10 years	$	78,614		$	78,932
Computer software	1-5 years	30,867			33,710
Buildings	10-40 years	25,472			25,041
Leasehold improvements	1-15 years	11,571			12,621
Furniture	1-13 years	8,618			8,601
Land		1,759			1,759
Property and equipment, gross		156,901			160,664
Less: Accumulated depreciation		(102,224		)	(98,740		)
Property and equipment, net		$	54,677		$	61,924

Goodwill and Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2016

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:



	December 31, 2016					December 31, 2015
(in thousands)	Gross Carrying Amount		Accumulated Amortization			Gross Carrying Amount		Accumulated Amortization
Finite-lived intangible assets:
Developed software and core technologies (3 – 11 years)	$	338,594	$	(275,130	)	$	336,262	$	(251,201	)
Customer lists and contract backlog (5 – 15 years)	159,549		(88,414		)	159,885		(76,160		)
Trade names (2 – 10 years)	127,952		(90,289		)	127,903		(76,493		)
Total	$	626,095	$	(453,833	)	$	624,050	$	(403,854	)
Indefinite-lived intangible assets:
Trade names	$	357				$	357

Estimated Future Amortization Expense for Intangible Assets

As of December 31, 2016, estimated future amortization expense for the intangible assets reflected above is as follows:



(in thousands)
2017	$	47,937
2018	34,643
2019	21,332
2020	20,325
2021	16,199
Thereafter	31,826
Total intangible assets subject to amortization, net	172,262
Indefinite-lived trade name	357
Other intangible assets, net	$	172,619

Changes in Goodwill

The changes in goodwill during the years ended December 31, 2016 and 2015 are as follows:



(in thousands)	2016			2015
Beginning balance - January 1	$	1,332,348		$	1,312,182
Acquisitions	6,184			28,561
Adjustments⁽¹⁾	(1		)	(4,573		)
Currency translation	(1,316		)	(3,822		)
Ending balance - December 31	$	1,337,215		$	1,332,348

Fair Value Measurement (Tables)

12 Months Ended

Dec. 31, 2016

Fair Value Disclosures [Abstract]

Fair Value of Assets and Liabilities Measured on Recurring Basis

The following tables provide the assets and liabilities carried at fair value and measured on a recurring basis:



			Fair Value Measurements at Reporting Date Using:
(in thousands)	December 31, 2016		Quoted Prices in Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets
Cash equivalents	$	333,975	$	333,975	$	—	$	—
Short-term investments	$	381	$	—	$	381	$	—
Deferred compensation plan investments	$	459	$	459	$	—	$	—



				Fair Value Measurements at Reporting Date Using:
(in thousands)	December 31, 2015			Quoted Prices in Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets
Cash equivalents	$	356,924		$	356,924	$	—	$	—
Short-term investments	$	446		$	—	$	446	$	—
Liabilities
Contingent consideration	$	(1,376	)	$	—	$	—	$	(1,376	)

Changes in Level 3 Liabilities Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs



	Fair Value Measurement Using Significant Unobservable Inputs
(in thousands)	Contingent Consideration
Balance as of January 1, 2015	$	2,621
Contingent payments	(1,456		)
Interest expense and foreign exchange activity included in earnings	211
Balance as of December 31, 2015	$	1,376
Contingent payments	(1,448		)
Interest expense and foreign exchange activity included in earnings	72
Balance as of December 31, 2016	$	—

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2016

Income Tax Disclosure [Abstract]

Components Of Income Before Income Taxes

Income before income taxes includes the following components:



	Year Ended December 31,
(in thousands)	2016		2015		2014
Domestic	$	340,251	$	325,097	$	291,042
Foreign	40,064		31,668		57,097
Total	$	380,315	$	356,765	$	348,139

Components Of Provision For Income Taxes

The provision for income taxes is composed of the following:



	Year Ended December 31,
(in thousands)	2016			2015			2014
Current:
Federal	$	99,783		$	93,853		$	80,620
State	8,338			7,733			7,192
Foreign	17,479			17,854			24,495
Deferred:
Federal	(13,368		)	(14,472		)	(18,536		)
State	(1,036		)	(1,987		)	(1,915		)
Foreign	3,483			1,263			1,593
Total	$	114,679		$	104,244		$	93,449

Reconciliation Of U.S. Federal Statutory Tax Rate To Consolidated Effective Tax Rate

The reconciliation of the U.S. federal statutory tax rate to the consolidated effective tax rate is as follows:



	Year Ended December 31,
	2016		2015		2014
Federal statutory tax rate	35.0	%	35.0	%	35.0	%
State income taxes, net of federal benefit	1.6		1.1		1.2
Uncertain tax positions	(0.2	)	(0.4	)	(0.9	)
Research and development credits	(1.0	)	(1.1	)	(1.1	)
Benefit from restructuring activities	(2.2	)	(2.7	)	(4.1	)
Domestic production activity benefit	(3.7	)	(3.1	)	(3.5	)
Other	0.7		0.4		0.2
	30.2	%	29.2	%	26.8	%

Components Of Deferred Tax Assets And Liabilities

The components of deferred tax assets and liabilities are as follows:



	December 31,
(in thousands)	2016			2015
Deferred tax assets:
Net operating loss carryforwards	$	32,969		$	40,939
Stock-based compensation	23,652			23,258
Employee benefits	17,187			17,044
Uncertain tax positions	11,562			10,233
Deferred revenue	6,382			8,603
Research and development credits	3,889			3,562
Allowance for doubtful accounts	2,078			1,888
Other	3,163			3,240
Valuation allowance	(1,625		)	(603		)
	99,257			108,164
Deferred tax liabilities:
Other intangible assets	(56,195		)	(73,933		)
Property and equipment	(2,994		)	(3,426		)
	(59,189		)	(77,359		)
Net deferred tax assets	$	40,068		$	30,805

Reconciliation Of Unrecognized Tax Benefits

The following is a reconciliation of the total amounts of unrecognized tax benefits:



	Year Ended December 31,
(in thousands)	2016			2015			2014
Unrecognized tax benefit as of January 1	$	16,067		$	16,342		$	19,590
Gross increases—tax positions in prior period	983			64			488
Gross decreases—tax positions in prior period	(2,502		)	(850		)	(3,715		)
Gross increases—tax positions in current period	2,725			4,064			2,513
Reductions due to a lapse of the applicable statute of limitations	(927		)	(2,808		)	(1,924		)
Changes due to currency fluctuation	(348		)	(653		)	(610		)
Settlements	(789		)	(92		)	—
Unrecognized tax benefit as of December 31	$	15,209		$	16,067		$	16,342

Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2016

Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]

Stock-Based Compensation Expense

Total stock-based compensation expense recognized for the years ended December 31, 2016, 2015 and 2014 is as follows:



	Year Ended December 31,
(in thousands, except per share amounts)	2016			2015			2014
Cost of sales:
Software licenses	$	701		$	745		$	1,776
Maintenance and service	1,578			1,868			2,035
Operating expenses:
Selling, general and administrative	15,990			17,153			17,073
Research and development	15,078			14,185			15,977
Stock-based compensation expense before taxes	33,347			33,951			36,861
Related income tax benefits	(10,538		)	(11,656		)	(10,927		)
Stock-based compensation expense, net of taxes	$	22,809		$	22,295		$	25,934
Net impact on earnings per share:
Basic earnings per share	$	(0.26	)	$	(0.25	)	$	(0.28	)
Diluted earnings per share	$	(0.26	)	$	(0.24	)	$	(0.28	)

Summary Of Stock Options

Information regarding stock option transactions is summarized below:



	Year Ended December 31,
	2016				2015				2014
(options in thousands)	Options		Weighted- Average Exercise Price		Options		Weighted- Average Exercise Price		Options		Weighted- Average Exercise Price
Outstanding, beginning of year	3,986		$	51.07	4,932		$	48.76	6,166		$	44.77
Granted	260		$	94.38	57		$	88.10	150		$	81.09
Issued pursuant to acquisitions	—		$	—	8		$	12.26	21		$	23.26
Exercised	(1,082	)	$	45.57	(975	)	$	40.52	(1,266	)	$	31.36
Forfeited	(28	)	$	72.07	(36	)	$	70.15	(139	)	$	61.11
Outstanding, end of year	3,136		$	56.37	3,986		$	51.07	4,932		$	48.76
Vested and Exercisable, end of year	2,762		$	51.80	3,539		$	48.29	3,958		$	44.22



	2016		2015		2014
Weighted-Average Remaining Contractual Term (in years)
Outstanding	4.62		4.85		5.53
Vested and Exercisable	4.04		4.53		5.00
Aggregate Intrinsic Value (in thousands)
Outstanding	$	113,822	$	165,131	$	163,932
Vested and Exercisable	$	112,379	$	156,487	$	149,536

Information Regarding Stock Options Outstanding

Information regarding stock options outstanding as of December 31, 2016 is summarized below:



(options in thousands)	Options Outstanding				Options Exercisable
Range of Exercise Prices	Options	Weighted- Average Remaining Contractual Life (years)	Weighted- Average Exercise Price		Options	Weighted- Average Exercise Price
$5.91 - $40.89	874	2.35	$	34.25	868	$	34.39
$41.33 - $58.67	1,175	4.25	$	54.02	1,175	$	54.02
$61.68 - $69.70	641	5.71	$	67.38	641	$	67.38
$73.45 - $95.09	446	8.47	$	90.11	78	$	83.78

Stock Options [Member]

Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]

Assumptions To Estimate Fair Value Of Stock Awards

The table below presents the weighted average input assumptions used and resulting fair values for options granted or issued in business combinations during each respective year:



	Year Ended December 31,
	2016	2015	2014
Risk-free interest rate	1.19% to 1.93%	1.18% to 1.65%	1.49% to 1.76%
Expected dividend yield	—%	—%	—%
Expected volatility	24%	25%	35%
Expected term	5.7 years	5.6 years	5.7 years
Weighted-average fair value per share	$23.96	$30.83	$32.26

Restricted Stock Units (RSUs) [Member]

Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]

Assumptions To Estimate Fair Value Of Stock Awards



	Year Ended December 31,
Assumptions used in Monte Carlo lattice pricing model	2016	2015	2014
Risk-free interest rate	1.0%	1.1%	0.7%
Expected dividend yield	—%	—%	—%
Expected volatility—ANSYS stock price	21%	23%	25%
Expected volatility—NASDAQ Composite Index	16%	14%	15%
Expected term	2.8 years	2.8 years	2.8 years
Correlation factor	0.65	0.60	0.70

Stock Repurchase Program (Tables)

12 Months Ended

Dec. 31, 2016

Class of Stock Disclosures [Abstract]

Stock Repurchase Program

Under the Company's stock repurchase program, the Company repurchased shares as follows:



	Year Ended December 31,
(in thousands, except per share data)	2016		2015		2014
Number of shares repurchased	3,700		3,833		2,977
Average price paid per share	$	90.90	$	88.16	$	78.54
Total cost	$	336,335	$	337,910	$	233,793

Leases (Tables)

12 Months Ended

Dec. 31, 2016

Leases [Abstract]

Schedule of Future Minimum Rental Payments for Operating Leases

Future minimum lease payments, including termination fees, under noncancellable operating leases for office space in effect at December 31, 2016 are as follows:



(in thousands)
2017	$	12,516
2018	9,901
2019	9,178
2020	6,961
2021	6,132
Thereafter	21,204
Total	$	65,892

Geographic Information (Tables)

12 Months Ended

Dec. 31, 2016

Segments, Geographical Areas [Abstract]

Schedule of Revenue from External Customers Attributed to Foreign Countries by Geographic Area

Revenue by geographic area is as follows:



	Year Ended December 31,
(in thousands)	2016		2015		2014
United States	$	367,937	$	354,433	$	320,327
Japan	120,160		104,299		108,757
Germany	99,814		94,546		99,714
South Korea	56,790		55,142		55,606
France	49,294		49,444		58,785
Canada	13,284		13,314		14,034
Other European	139,813		145,985		159,011
Other international	141,373		125,590		119,787
Total revenue	$	988,465	$	942,753	$	936,021

Schedule of Disclosure on Geographic Areas, Long-Lived Assets in Individual Foreign Countries by Country

Property and equipment by geographic area is as follows:



	December 31,
(in thousands)	2016		2015
United States	$	43,810	$	47,971
Europe	4,753		6,808
India	3,033		3,286
Other international	3,081		3,859
Total property and equipment, net	$	54,677	$	61,924

Unconditional Purchase Obligations (Tables)

12 Months Ended

Dec. 31, 2016

Unconditional Purchase Obligations (Excluding Capital Stock Redemptions) [Abstract]

Unrecorded Unconditional Purchase Obligations Disclosure

Future expenditures under unconditional purchase obligations in effect as of December 31, 2016 are as follows:



(in thousands)
2017	$	14,134
2018	10,288
2019	9,724
2020	2,617
2021	652
Total	$	37,415

Organization - Additional Information (Detail)	12 Months Ended
Organization - Additional Information (Detail)	Dec. 31, 2016 Segment
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of operating segments	1

Summary Of Significant Accounting Policies - Additional Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Amortization	$ 50,847	$ 58,149	$ 61,041
Provisions for doubtful accounts	2,009	1,304	2,104
Net foreign exchange gains (losses)	$ 77	$ 486	$ (1,649)
Minimum [Member]
Semiconductor product licenses, term	24 months
Property and equipment, estimated useful lives (years)	1 year
Maximum [Member]
Semiconductor product licenses, term	36 months
Property and equipment, estimated useful lives (years)	40 years
Customer Concentration Risk [Member]
Number of customers with more than five percent of revenue	0	0	0

Summary Of Significant Accounting Policies (Summary Of Cash And Cash Equivalents) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accounting Policies [Abstract]
Cash accounts	$ 488,504	$ 427,244
Money market funds	333,975	356,924
Cash and cash equivalents	$ 822,479	$ 784,168	$ 788,064	$ 742,486
Cash accounts, % of Total	59.40%	54.50%
Money market funds, % of Total	40.60%	45.50%

Summary Of Significant Accounting Policies (Schedule Of Risk Concentration) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Concentration Risk [Line Items]
Cash and cash equivalents, at carrying value	$ 822,479	$ 784,168	$ 788,064	$ 742,486
Customer Concentration Risk [Member]
Concentration Risk [Line Items]
Channel partner concentration risk, percentage	24.40%	24.20%	24.90%
Credit Concentration Risk [Member]
Concentration Risk [Line Items]
Cash and cash equivalents held in excess of deposit insurance, foreign and domestic	$ 805,374	$ 763,400
Largest balance of cash and cash equivalents held with one financial institution, foreign and domestic	$ 377,602	$ 440,650
1st Largest Channel Partner [Member] \| Customer Concentration Risk [Member]
Concentration Risk [Line Items]
Channel partner concentration risk, percentage	5.00%	5.00%	4.00%
2nd Largest Channel Partner [Member] \| Customer Concentration Risk [Member]
Concentration Risk [Line Items]
Channel partner concentration risk, percentage	2.00%	2.00%	2.00%
United States \| Credit Concentration Risk [Member]
Concentration Risk [Line Items]
Cash and cash equivalents, at carrying value	$ 593,348	$ 539,031
FOREIGN \| Credit Concentration Risk [Member]
Concentration Risk [Line Items]
Cash and cash equivalents, at carrying value	$ 229,131	$ 245,137

Summary Of Significant Accounting Policies (Basic And Diluted Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accounting Policies [Abstract]
Net income	$ 265,636	$ 252,521	$ 254,690
Weighted average shares outstanding - basic	87,227	89,561	92,067
Dilutive effect of stock plans	1,742	1,941	2,127
Weighted average shares outstanding - diluted	88,969	91,502	94,194
Basic earnings per share	$ 3.05	$ 2.82	$ 2.77
Diluted earnings per share	$ 2.99	$ 2.76	$ 2.70
Anti-dilutive options	260	206	718

Acquisition - Additional Information (Detail) - USD ($) $ in Thousands			12 Months Ended
	Apr. 30, 2014	Jan. 03, 2014	Dec. 31, 2016	Dec. 31, 2015	Apr. 30, 2015	Jan. 03, 2015	Dec. 31, 2014
Business Acquisition [Line Items]
Goodwill			$ 1,337,215	$ 1,332,348			$ 1,312,182
Other Acquisitions [Member]
Business Acquisition [Line Items]
Total consideration transferred at fair value			10,300	49,700
Business combination, historical carrying value of acquired deferred revenue				900
Acquired deferred revenue, impact on reported revenue			103	800
Deferred revenue				0
SpaceClaim Corporation [Member]
Business Acquisition [Line Items]
Total consideration transferred at fair value	$ 84,960
Business combination, historical carrying value of acquired deferred revenue	$ 3,300
Acquired deferred revenue, impact on reported revenue				600			2,000
Goodwill, period increase (decrease)					$ (4,800)
Deferred revenue			(700)
Goodwill			48,453
Reaction Design [Member]
Business Acquisition [Line Items]
Total consideration transferred at fair value		$ 19,100
Business combination, historical carrying value of acquired deferred revenue		$ 2,300
Acquired deferred revenue, impact on reported revenue				$ 300			$ 2,000
Goodwill, period increase (decrease)						$ 1,900
Deferred revenue			0
Finite-lived intangibles			7,000
Goodwill			$ 9,200
Noncontrolling interest, period decrease						$ (600)
Minimum [Member] \| Reaction Design [Member]
Business Acquisition [Line Items]
Finite-lived intangible asset, useful life			2 years
Maximum [Member] \| Reaction Design [Member]
Business Acquisition [Line Items]
Finite-lived intangible asset, useful life			11 years

Fair Value of Consideration Transferred (Detail) - USD ($) $ in Thousands		12 Months Ended
	Apr. 30, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Business Acquisition [Line Items]
ANSYS replacement stock options		$ 0	$ 3,528	$ 68
SpaceClaim Corporation [Member]
Business Acquisition [Line Items]
Cash payments for acquisitions	$ 84,892
ANSYS replacement stock options	68
Total consideration transferred at fair value	$ 84,960

Recognized Amounts of Identifiable Assets Acquired and Liabilities Assumed (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Business Combination, Separately Recognized Transactions [Line Items]
Goodwill	$ 1,337,215	$ 1,332,348	$ 1,312,182
SpaceClaim Corporation [Member]
Business Combination, Separately Recognized Transactions [Line Items]
Cash	723
Accounts receivable and other tangible assets	1,857
Deferred tax assets	9,288
Accounts payable and other liabilities	(2,011)
Deferred revenue	(700)
Total identifiable net assets	36,507
Goodwill	48,453
SpaceClaim Corporation [Member] \| Developed Software
Business Combination, Separately Recognized Transactions [Line Items]
Finite-lived intangibles	15,800
SpaceClaim Corporation [Member] \| Customer Relationships
Business Combination, Separately Recognized Transactions [Line Items]
Finite-lived intangibles	9,400
SpaceClaim Corporation [Member] \| Trade Names
Business Combination, Separately Recognized Transactions [Line Items]
Finite-lived intangibles	1,300
SpaceClaim Corporation [Member] \| Contract Backlog
Business Combination, Separately Recognized Transactions [Line Items]
Finite-lived intangibles	550
SpaceClaim Corporation [Member] \| Non-Compete Agreements
Business Combination, Separately Recognized Transactions [Line Items]
Finite-lived intangibles	$ 300

Recognized Amounts of Identifiable Assets Acquired and Liabilities Assumed Estimated Useful Lives (Detail)	12 Months Ended
	Dec. 31, 2016
SpaceClaim Corporation [Member] \| Developed Software
Business Combination, Separately Recognized Transactions [Line Items]
Finite-lived intangible asset, useful life	10 years
SpaceClaim Corporation [Member] \| Customer Relationships
Business Combination, Separately Recognized Transactions [Line Items]
Finite-lived intangible asset, useful life	6 years
SpaceClaim Corporation [Member] \| Trade Names
Business Combination, Separately Recognized Transactions [Line Items]
Finite-lived intangible asset, useful life	6 years
SpaceClaim Corporation [Member] \| Contract Backlog
Business Combination, Separately Recognized Transactions [Line Items]
Finite-lived intangible asset, useful life	6 years
SpaceClaim Corporation [Member] \| Non-Compete Agreements
Business Combination, Separately Recognized Transactions [Line Items]
Finite-lived intangible asset, useful life	2 years
Maximum [Member] \| Trade Names
Business Combination, Separately Recognized Transactions [Line Items]
Finite-lived intangible asset, useful life	10 years
Maximum [Member] \| Reaction Design [Member]
Business Combination, Separately Recognized Transactions [Line Items]
Finite-lived intangible asset, useful life	11 years
Minimum [Member] \| Trade Names
Business Combination, Separately Recognized Transactions [Line Items]
Finite-lived intangible asset, useful life	2 years
Minimum [Member] \| Reaction Design [Member]
Business Combination, Separately Recognized Transactions [Line Items]
Finite-lived intangible asset, useful life	2 years

Other Receivables and Current Assets - Additional Information (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Other receivables and current assets	$ 239,349	$ 200,233
Receivables related to unrecognized revenue
Other receivables and current assets	199,119	170,186
Income taxes receivable, including overpayments and refunds
Other receivables and current assets	15,718	7,877
Prepaid expenses and other current assets
Other receivables and current assets	$ 24,512	$ 22,170

Property and Equipment - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Depreciation expense related to property and equipment	$ 18.7	$ 19.5	$ 20.9

Property and Equipment (Components Of Property and Equipment) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 156,901	$ 160,664
Less: Accumulated depreciation	(102,224)	(98,740)
Property and equipment, net	54,677	61,924
Equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	78,614	78,932
Computer Software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	30,867	33,710
Buildings
Property, Plant and Equipment [Line Items]
Property and equipment, gross	25,472	25,041
Leasehold Improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	11,571	12,621
Furniture
Property, Plant and Equipment [Line Items]
Property and equipment, gross	8,618	8,601
Land
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 1,759	$ 1,759
Minimum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives (years)	1 year
Minimum [Member] \| Equipment
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives (years)	1 year
Minimum [Member] \| Computer Software
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives (years)	1 year
Minimum [Member] \| Buildings
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives (years)	10 years
Minimum [Member] \| Leasehold Improvements
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives (years)	1 year
Minimum [Member] \| Furniture
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives (years)	1 year
Maximum [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives (years)	40 years
Maximum [Member] \| Equipment
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives (years)	10 years
Maximum [Member] \| Computer Software
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives (years)	5 years
Maximum [Member] \| Buildings
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives (years)	40 years
Maximum [Member] \| Leasehold Improvements
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives (years)	15 years
Maximum [Member] \| Furniture
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives (years)	13 years

Intangible Assets and Estimated Useful Lives (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Intangible Assets [Line Items]
Amortized intangible assets, gross carrying amount	$ 626,095	$ 624,050
Amortized intangible assets, accumulated amortization	(453,833)	(403,854)
Unamortized intangible assets, gross carrying amount	357
Developed Software and Core Technologies
Intangible Assets [Line Items]
Amortized intangible assets, gross carrying amount	338,594	336,262
Amortized intangible assets, accumulated amortization	(275,130)	(251,201)
Customer Lists and Contract Backlog
Intangible Assets [Line Items]
Amortized intangible assets, gross carrying amount	159,549	159,885
Amortized intangible assets, accumulated amortization	(88,414)	(76,160)
Trade Names
Intangible Assets [Line Items]
Amortized intangible assets, gross carrying amount	127,952	127,903
Amortized intangible assets, accumulated amortization	(90,289)	(76,493)
Trade Names
Intangible Assets [Line Items]
Unamortized intangible assets, gross carrying amount	$ 357	$ 357

Intangible Assets and Estimated Useful Lives	12 Months Ended
Intangible Assets and Estimated Useful Lives	Dec. 31, 2016
Developed Software and Core Technologies \| Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life	3 years
Developed Software and Core Technologies \| Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life	11 years
Customer Lists and Contract Backlog \| Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life	5 years
Customer Lists and Contract Backlog \| Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life	15 years
Trade Names \| Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life	2 years
Trade Names \| Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible asset, useful life	10 years

Goodwill and Intangible Assets - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization	$ 50,847	$ 58,149	$ 61,041

Estimated Future Amortization Expense for Intangible Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
2017	$ 47,937
2018	34,643
2019	21,332
2020	20,325
2021	16,199
Thereafter	31,826
Total intangible assets subject to amortization, net	172,262
Indefinite-lived trade name	357
Other intangible assets, net	$ 172,619	$ 220,553

Changes in Goodwill (Detail) - USD ($) $ in Thousands	12 Months Ended
Changes in Goodwill (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Goodwill [Roll Forward]
Beginning balance	$ 1,332,348	$ 1,312,182
Acquisitions	6,184	28,561
Adjustments	(1)	(4,573)
Currency translation	(1,316)	(3,822)
Ending balance	$ 1,337,215	$ 1,332,348

Fair Value of Assets and Liabilities Measured on Recurring Basis (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	$ 333,975	$ 356,924
Short-term investments	381	446
Deferred compensation plan investments	459
Contingent consideration		(1,376)
Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	333,975	356,924
Short-term investments	0	0
Deferred compensation plan investments	459
Contingent consideration		0
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	381	446
Deferred compensation plan investments	0
Contingent consideration		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
Contingent consideration		$ (1,376)

- Definition

Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(12))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Trading Securities
-URI http://asc.fasb.org/extlink&oid=6526789

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(5))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(6))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 35
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=27723805&loc=d3e24584-111560

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(2))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=65884222&loc=d3e22054-111558

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(1))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Available-for-Sale Securities
-URI http://asc.fasb.org/extlink&oid=6505594

+ Details

Fair Value Measurement - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2016
Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments maturity	3 months
Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments maturity	1 year

Changes in Level 3 Liabilities Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs (Detail) - Significant Unobservable Inputs (Level 3) - Contingent Consideration - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 1,376	$ 2,621
Contingent payments	(1,448)	(1,456)
Interest expense and foreign exchange activity included in earnings	72	211
Ending balance	$ 0	$ 1,376

Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Income Tax Contingency [Line Items]
Amount in excess of the amount for financial reporting over the tax bases	$ 199,000
Deferred tax liabilities, undistributed foreign earnings	35,000
Deferred tax assets, operating loss carryforwards, foreign	13,200
Deferred tax assets, valuation allowance	1,625	$ 603
Valuation allowance, deferred tax asset, increase, amount	1,000
Deferred tax assets, operating loss carryforwards, state and local	1,200
Tax credit carryforwards	5,200
Significant change in unrecognized tax benefits is reasonably possible, amount of unrecorded benefit	100
Unrecognized tax benefits that would impact effective tax rate	9,200
Penalty expense	800
Interest benefit	100
Liability for penalties	2,700	1,900
Liability for interest	2,800	$ 2,700
Subject To Expiration [Member]
Income Tax Contingency [Line Items]
Tax credit carryforwards	4,300
Subject To Utilization Limitations [Member]
Income Tax Contingency [Line Items]
Tax credit carryforwards	3,000
Not Subject To Expiration [Member]
Income Tax Contingency [Line Items]
Tax credit carryforwards	900
Foreign Country [Member]
Income Tax Contingency [Line Items]
Net operating loss carryforwards	76,900
Federal Domestic [Member]
Income Tax Contingency [Line Items]
Net operating loss carryforwards	28,700
Operating Loss Carryforward With No Expiration Date [Member] \| Foreign Country [Member]
Income Tax Contingency [Line Items]
Net operating loss carryforwards	28,200
Subject To Expiration [Member] \| Foreign Country [Member]
Income Tax Contingency [Line Items]
Net operating loss carryforwards	$ 48,700
Earliest Tax Year [Member]
Income Tax Contingency [Line Items]
Tax credit carryforward, expiration date	Jan. 01, 2017
Years open to examination	2013
Earliest Tax Year [Member] \| Foreign Country [Member]
Income Tax Contingency [Line Items]
Operating loss carryforwards, expiration date	Jan. 01, 2019
Earliest Tax Year [Member] \| Federal Domestic [Member]
Income Tax Contingency [Line Items]
Operating loss carryforwards, expiration date	Jan. 01, 2020
Earliest Tax Year [Member] \| State and Local Jurisdiction [Member]
Income Tax Contingency [Line Items]
Operating loss carryforwards, expiration date	Jan. 01, 2017
Latest Tax Year [Member]
Income Tax Contingency [Line Items]
Tax credit carryforward, expiration date	Dec. 31, 2036
Years open to examination	2016
Latest Tax Year [Member] \| Foreign Country [Member]
Income Tax Contingency [Line Items]
Operating loss carryforwards, expiration date	Dec. 31, 2025
Latest Tax Year [Member] \| Federal Domestic [Member]
Income Tax Contingency [Line Items]
Operating loss carryforwards, expiration date	Dec. 31, 2034
Latest Tax Year [Member] \| State and Local Jurisdiction [Member]
Income Tax Contingency [Line Items]
Operating loss carryforwards, expiration date	Dec. 31, 2035
Valuation Allowance, Operating Loss Carryforwards [Member] \| Foreign Country [Member]
Income Tax Contingency [Line Items]
Deferred tax assets, valuation allowance	$ 13,200

Income Taxes (Components Of Income Before Income Taxes) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Domestic	$ 340,251	$ 325,097	$ 291,042
Foreign	40,064	31,668	57,097
Income before income tax provision	$ 380,315	$ 356,765	$ 348,139

Income Taxes (Components Of Provision For Income Taxes) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Current, Federal	$ 99,783	$ 93,853	$ 80,620
Current, State	8,338	7,733	7,192
Current, Foreign	17,479	17,854	24,495
Deferred, Federal	(13,368)	(14,472)	(18,536)
Deferred, State	(1,036)	(1,987)	(1,915)
Deferred, Foreign	3,483	1,263	1,593
Total	$ 114,679	$ 104,244	$ 93,449

Income Taxes (Reconciliation Of U.S. Federal Statutory Tax Rate To Consolidated Effective Tax Rate) (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Federal statutory tax rate	35.00%	35.00%	35.00%
State income taxes, net of federal benefit	1.60%	1.10%	1.20%
Uncertain tax positions	(0.20%)	(0.40%)	(0.90%)
Research and development credits	(1.00%)	(1.10%)	(1.10%)
Benefit from restructuring activities	(2.20%)	(2.70%)	(4.10%)
Domestic production activity benefit	(3.70%)	(3.10%)	(3.50%)
Other	0.70%	0.40%	0.20%
Consolidated effective tax rate	30.20%	29.20%	26.80%

Income Taxes (Components Of Deferred Tax Assets And Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Net operating loss carryforwards	$ 32,969	$ 40,939
Stock-based compensation	23,652	23,258
Employee benefits	17,187	17,044
Uncertain tax positions	11,562	10,233
Deferred revenue	6,382	8,603
Research and development credits	3,889	3,562
Allowance for doubtful accounts	2,078	1,888
Other	3,163	3,240
Valuation allowance	(1,625)	(603)
Deferred tax assets	99,257	108,164
Other intangible assets	(56,195)	(73,933)
Property and equipment	(2,994)	(3,426)
Deferred tax liabilities	(59,189)	(77,359)
Net deferred tax assets	$ 40,068	$ 30,805

Income Taxes (Reconciliation Of Unrecognized Tax Benefits) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefit as of January 1	$ 16,067	$ 16,342	$ 19,590
Gross increases-tax positions in prior period	983	64	488
Gross decreases-tax positions in prior period	(2,502)	(850)	(3,715)
Gross increases-tax positions in current period	2,725	4,064	2,513
Reductions due to a lapse of the applicable statute of limitations	(927)	(2,808)	(1,924)
Changes due to currency fluctuation	(348)	(653)	(610)
Settlements	(789)	(92)	0
Unrecognized tax benefit as of December 31	$ 15,209	$ 16,067	$ 16,342

Pension And Profit-Sharing Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Contribution Plan Disclosure [Line Items]
Expenses related to retirement programs	$ 9.1	$ 8.4	$ 8.9
Four Zero One K Plan [Member]
Defined Contribution Plan Disclosure [Line Items]
Maximum annual contributions per employee, percent	4.25%
Minimum working hours per employee required to be eligible for discretionary contribution	1000 hours
First Three Percent Of Employee Pay [Member] \| Four Zero One K Plan [Member]
Defined Contribution Plan Disclosure [Line Items]
Percentage of employee contribution employer matches	100.00%
Percentage of employee pay employer matches	3.00%
More Than Three Percent Up To Eight Percent Of Employee Pay [Member] \| Four Zero One K Plan [Member]
Defined Contribution Plan Disclosure [Line Items]
Percentage of employee contribution employer matches	25.00%
Percentage of employee pay employer matches	5.00%

Stock-Based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Shares authorized for grant under the plan	39,800,000.0	39,800,000.0
Percentage of voting interest to be held by optionee		10.00%
Exercise price as a percentage of fair value at the time of grant		110.00%
Expiration period of options from the date of grant		10 years
Expiration period for optionee who meets the 10% criteria		5 years
Vesting period		4 years
Maximum months after sale event where awards fully vest when service relationship terminated without cause		18 months
Maximum number of days that may be granted to terminated employee to exercise awards prior to termination		15 days
Share-based compensation arrangement by share-based payment award, options, vested in period, fair value		$ 7,400	$ 12,300	$ 19,500
Total unrecognized estimated compensation cost	$ 8,200	$ 8,200
Weighted-average period of recognition of unrecognized compensation cost (years)		2 years 1 month
Total intrinsic value of options exercised during the period		$ 49,800	47,100	60,600
Unvested options	400,000	400,000
Aggregate intrinsic value of unvested options	$ 1,400	$ 1,400
Weighted-average exercise price of unvested options	$ 90.12	$ 90.12
Weighted-average remaining contractual term of unvested stock options (years)		8 years 11 months
Employee service share-based compensation, cash received from exercise of stock options		$ 49,300
Tax benefit from exercise of stock options		18,600
Stock-based compensation expense		33,347	33,951	36,861
Fair value of stock options and restricted stock awards assumed in connection with acquisitions		$ 0	$ 3,528	$ 68
Performance Shares [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of awards granted		35,000	34,450	47,000
Value of the restricted stock units on the grant date	78.71	$ 78.71	$ 81.61	$ 65.94
Stock-based compensation expense		$ 2,200	$ 3,100	$ 2,500
Restricted stock units earned		5,973
Restricted Stock [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of awards granted		63,462	51,795	20,667
Value of the restricted stock units on the grant date	84.61	$ 84.61	$ 86.38	$ 81.52
Stock-based compensation expense		$ 400	$ 400	$ 100
Share-based compensation arrangement by share-based payment award, shares issued in period		35,000	115,485	39,900
Restricted stock units earned		7,625
Restricted Stock Units (RSUs) [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of awards granted		488,622	344,500	364,150
Value of the restricted stock units on the grant date	$ 88.51	$ 88.51	$ 86.34	$ 82.13
Stock-based compensation expense		$ 19,100	$ 12,500	$ 5,800
Restricted stock units earned		162,019	85,713
Share-based compensation arrangement by share-based payment award, equity instruments other than options, nonvested, number	838,327	838,327	571,462	344,750
Deferred Stock Units [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting period		1 year
Number of awards granted		38,400
Stock-based compensation expense		$ 1,900	$ 4,000	$ 3,500
Restricted stock units earned	184,099
Diversified deferred stock awards	5,000	5,000
Other Acquisitions [Member] \| Restricted Stock [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Value of the restricted stock units on the grant date			$ 90.48
Stock-based compensation expense		$ 1,200	$ 600
Share-based compensation arrangement by share-based payment award, shares issued in period			68,451
Stock issued during period, value, restricted stock award			$ 6,200
Apache Design Inc [Member] \| Restricted Stock [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Stock-based compensation expense				$ 4,700
Minimum [Member] \| Performance Shares [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting period		1 year
Minimum [Member] \| Restricted Stock Units (RSUs) [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting period		3 years
Maximum [Member] \| Performance Shares [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting period		3 years
Maximum [Member] \| Restricted Stock Units (RSUs) [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Vesting period		4 years

Stock-Based Compensation (Summary Of Stock Options) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Outstanding, beginning of year, Weighted-Average Exercise Price	$ 51.07	$ 48.76	$ 44.77
Granted, Weighted-Average Exercise Price	94.38	88.10	81.09
Issued pursuant to acquisitions, Weighted-Average Exercise Price	0.00	12.26	23.26
Exercised, Weighted-Average Exercise Price	45.57	40.52	31.36
Forfeited, Weighted-Average Exercise Price	72.07	70.15	61.11
Outstanding, end of year, Weighted-Average Exercise Price	56.37	51.07	48.76
Vested and Exercisable, end of year, Weighted-Average Exercise Price	$ 51.80	$ 48.29	$ 44.22
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding, beginning of year, Options	3,986	4,932	6,166
Granted, Options	260	57	150
Issued pursuant to acquisitions, Options	0	8	21
Exercised, Options	(1,082)	(975)	(1,266)
Forfeited, Options	(28)	(36)	(139)
Outstanding, end of year, Options	3,136	3,986	4,932
Vested and Exercisable, end of year, Options	2,762	3,539	3,958
Outstanding, Weighted-Average Remaining Contractual Term (in years)	4 years 7 months 14 days	4 years 10 months 5 days	5 years 6 months 12 days
Vested and Exercisable, Weighted-Average Remaining Contractual Term (in years)	4 years 15 days	4 years 6 months 12 days	5 years
Outstanding, Aggregate Intrinsic Value	$ 113,822	$ 165,131	$ 163,932
Vested and Exercisable, Aggregate Intrinsic Value	$ 112,379	$ 156,487	$ 149,536

Stock-Based Compensation (Stock-Based Compensation Expense) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense before taxes	$ 33,347	$ 33,951	$ 36,861
Stock-based compensation expense	33,347	33,951	36,861
Related income tax benefits	(10,538)	(11,656)	(10,927)
Stock-based compensation expense, net of taxes	$ 22,809	$ 22,295	$ 25,934
Basic earnings per share	$ (0.26)	$ (0.25)	$ (0.28)
Diluted earnings per share	$ (0.26)	$ (0.24)	$ (0.28)
Software Licenses
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense before taxes	$ 701	$ 745	$ 1,776
Maintenance And Service [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense before taxes	1,578	1,868	2,035
Selling, General And Administrative [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense before taxes	15,990	17,153	17,073
Research And Development [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense before taxes	$ 15,078	$ 14,185	$ 15,977

Stock-Based Compensation (Assumptions To Estimate Fair Value Of Stock Awards) (Details)	12 Months Ended
	Dec. 31, 2016 $ / shares	Dec. 31, 2015 $ / shares	Dec. 31, 2014 $ / shares
Stock Option Compensation Expense [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Risk-free interest rate, minimum	1.19%	1.18%	1.49%
Risk-free interest rate, maximum	1.93%	1.65%	1.76%
Expected dividend yield	0.00%	0.00%	0.00%
Expected volatility	24.00%	25.00%	35.00%
Expected term (in years)	5 years 8 months 7 days	5 years 7 months 7 days	5 years 8 months 7 days
Weighted-average fair value per share	$ 23.96	$ 30.83	$ 32.26
Restricted Stock Unit Compensation Expense [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Expected dividend yield	0.00%	0.00%	0.00%
Expected term (in years)	2 years 9 months 18 days	2 years 9 months 18 days	2 years 9 months 18 days
Risk-free interest rate	1.00%	1.10%	0.70%
Correlation factor	0.65	0.60	0.70
Restricted Stock Unit Compensation Expense [Member] \| ANSYS Stock Price [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Expected volatility	21.00%	23.00%	25.00%
Restricted Stock Unit Compensation Expense [Member] \| NASDAQ Composite Index [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Expected volatility	16.00%	14.00%	15.00%

Stock-Based Compensation (Information Regarding Stock Options Outstanding) (Details) shares in Thousands	12 Months Ended
	Dec. 31, 2016 $ / shares shares
$5.91 - $40.89
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Lower Limit	$ 5.91
Range of Exercise Prices, Upper Limit	$ 40.89
Options Outstanding, Options \| shares	874
Options Outstanding, Weighted-Average Remaining Contractual Life (years)	2 years 4 months 5 days
Options Outstanding, Weighted-Average Exercise Price	$ 34.25
Options Exercisable, Options \| shares	868
Options Exercisable, Weighted-Average Exercise Price	$ 34.39
$41.33 - $58.67
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Lower Limit	41.33
Range of Exercise Prices, Upper Limit	$ 58.67
Options Outstanding, Options \| shares	1,175
Options Outstanding, Weighted-Average Remaining Contractual Life (years)	4 years 3 months 1 day
Options Outstanding, Weighted-Average Exercise Price	$ 54.02
Options Exercisable, Options \| shares	1,175
Options Exercisable, Weighted-Average Exercise Price	$ 54.02
$61.68 - $69.70
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Lower Limit	61.68
Range of Exercise Prices, Upper Limit	$ 69.7
Options Outstanding, Options \| shares	641
Options Outstanding, Weighted-Average Remaining Contractual Life (years)	5 years 8 months 15 days
Options Outstanding, Weighted-Average Exercise Price	$ 67.38
Options Exercisable, Options \| shares	641
Options Exercisable, Weighted-Average Exercise Price	$ 67.38
$73.45 - $95.09
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Lower Limit	73.45
Range of Exercise Prices, Upper Limit	$ 95.09
Options Outstanding, Options \| shares	446
Options Outstanding, Weighted-Average Remaining Contractual Life (years)	8 years 5 months 20 days
Options Outstanding, Weighted-Average Exercise Price	$ 90.11
Options Exercisable, Options \| shares	78
Options Exercisable, Weighted-Average Exercise Price	$ 83.78

Stock Repurchase Program - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Feb. 17, 2017
Equity, Class of Treasury Stock [Line Items]
Number of shares repurchased	3,700,000	3,833,000	2,977,000
Average price paid per share	$ 90.90	$ 88.16	$ 78.54
Total cost	$ 336,335	$ 337,910	$ 233,793
Remaining number of shares authorized to be repurchased under stock repurchase program	1,300,000
Subsequent Event [Member]
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program, number of shares authorized to be repurchased				5,000,000

Employee Stock Purchase Plan (Details) - USD ($) $ in Thousands		12 Months Ended
	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, number of shares authorized	39,800,000.0	39,800,000.0
Share-based compensation arrangement by share-based payment award, expiration period		10 years
Stock-based compensation expense		$ 33,347	$ 33,951	$ 36,861
Employee Stock \| ANSYS 1996 Employee Stock Purchase Plan [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, number of shares authorized	1,800,000	1,800,000
Share-based compensation arrangement by share-based payment award, expiration period		6 months
Share-based compensation arrangement by share-based payment award, maximum employee subscription rate	10.00%	10.00%
Maximum number of shares per employee		3,840
Maximum employee subscription rate, value		$ 25
Share-based compensation arrangement by share-based payment award, shares issued in period	1,400,000
Stock-based compensation expense		$ 1,200	$ 1,000	$ 900
Maximum [Member] \| Employee Stock \| ANSYS 1996 Employee Stock Purchase Plan [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Eligibility, ownership percentage of voting power of all classes of stock of the company	5.00%	5.00%
Purchase price of common stock, percent		90.00%

Leases (Details) ft² in Thousands, $ in Thousands	12 Months Ended
Leases (Details) ft² in Thousands, $ in Thousands	Dec. 31, 2016 USD ($) ft²	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Operating Leased Assets [Line Items]
Lease rental expense incurred	$ 16,900	$ 16,500	$ 15,800
Future minimum lease payments	65,892
Future minimum lease payments, Year 1	12,516
Future minimum lease payments, Year 2	9,901
Future minimum lease payments, Year 3	9,178
Future minimum lease payments, Year 4	6,961
Future minimum lease payments, Year 5	6,132
Future minimum lease payments, Thereafter	$ 21,204
Lease Agreement Effective September 14, 2012 \| Canonsburg Office, New Company Headquarters
Operating Leased Assets [Line Items]
Area of real estate property \| ft²	186
Period of leased property	183 months
Base rent, years one through five	$ 4,300
Base rent, years six through ten	4,500
Base rent, years eleven through fifteen	4,700
Lease rental expense incurred	$ 4,400	$ 4,400	800
Amended Lease Agreement Effective January 1, 2004 \| Canonsburg Office
Operating Leased Assets [Line Items]
Lease rental expense incurred			$ 1,400

Royalty Agreements (Details) - USD ($) $ in Millions	12 Months Ended
Royalty Agreements (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Royalty Agreements [Abstract]
Royalty fees reported in cost of goods sold	$ 13.1	$ 11.8	$ 11.5

Revenue by Geographic Area (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 988,465	$ 942,753	$ 936,021
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	367,937	354,433	320,327
Japan
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	120,160	104,299	108,757
Germany
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	99,814	94,546	99,714
South Korea
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	56,790	55,142	55,606
France
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	49,294	49,444	58,785
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	13,284	13,314	14,034
Other European
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	139,813	145,985	159,011
Other international
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 141,373	$ 125,590	$ 119,787

Property and Equipment by Geographic Area (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property and equipment, net	$ 54,677	$ 61,924
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property and equipment, net	43,810	47,971
Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property and equipment, net	4,753	6,808
India
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property and equipment, net	3,033	3,286
Other international
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property and equipment, net	$ 3,081	$ 3,859

Unconditional Purchase Obligations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Unconditional Purchase Obligations (Excluding Capital Stock Redemptions) [Abstract]
Unconditional purchase obligations, beginning of year	$ 7,200	$ 5,300	$ 2,900
Future expenditures under purchase obligations, next twelve months	14,134
Future expenditures under purchase obligations, year two	10,288
Future expenditures under purchase obligations, year three	9,724
Future expenditures under purchase obligations, year four	2,617
Future expenditures under purchase obligations, year five	652
Future expenditures under purchase obligations	$ 37,415

Restructuring (Details) $ in Millions	12 Months Ended
Restructuring (Details) $ in Millions	Dec. 31, 2016 USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 2.4
Operating Income (Loss) [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges	3.4
Minimum [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring, expected cost remaining	7.0
Minimum [Member] \| Operating Income (Loss) [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring, expected cost remaining	10.0
Maximum [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring, expected cost remaining	10.0
Maximum [Member] \| Operating Income (Loss) [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring, expected cost remaining	$ 15.0

Employment-Related Settlement (Details) $ in Millions	Dec. 31, 2016 USD ($)
Other Liabilities [Abstract]
Other liabilities	$ 4.7

Contingencies and Commitments - Additional Information (Detail) $ in Millions	Dec. 31, 2016 USD ($)
Maximum [Member]
Other Commitments And Contingencies [Line Items]
Tax charges and related liabilities if the ruling is unfavorable	$ 7.0
French Research and Development Tax Credit, Denied by Tax Authority [Member]
Other Commitments And Contingencies [Line Items]
Tax charges and related liabilities if the ruling is unfavorable	0.8
French Research and Development Tax Credit, Claimed Credits with Risk of Denial by Tax Authority [Member]
Other Commitments And Contingencies [Line Items]
Tax charges and related liabilities if the ruling is unfavorable	$ 3.8

Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Movement in Valuation Allowances and Reserves [Roll Forward]
Provisions for doubtful accounts	$ 2,009	$ 1,304	$ 2,104
Allowance for Doubtful Accounts
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	5,200	5,500	5,700
Provisions for doubtful accounts	2,009	1,304	2,104
Deductions - returns and write-offs	1,509	1,604	2,304
Balance at end of year	$ 5,700	$ 5,200	$ 5,500