ANSYS (ANSS) 10-K 27 Feb 20 2019 FY Annual report Financial data

Document

Document - USD ($)	12 Months Ended
	Dec. 31, 2019	Feb. 20, 2020	Jun. 30, 2019
Entity Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2019
Document Transition Report	false
Entity File Number	0-20853
Entity Registrant Name	ANSYS, Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	04-3219960
Entity Address, Address Line One	2600 ANSYS Drive,
Entity Address, City or Town	Canonsburg,
Entity Address, State or Province	PA
Entity Address, Postal Zip Code	15317
City Area Code	844
Local Phone Number	462-6797
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 14,436,000,000
Entity Common Stock, Shares Outstanding		85,914,375
Amendment Flag	false
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Entity Central Index Key	0001013462
Current Fiscal Year End Date	--12-31
Nasdaq Stock Market LLC
Entity Information [Line Items]
Title of 12(b) Security	Common Stock, $0.01 par value per share
Trading Symbol	ANSS
Security Exchange Name	NASDAQ

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 872,094	$ 777,139
Short-term investments	288	225
Accounts receivable, less allowance for doubtful accounts of $8,700 and $8,000, respectively	433,479	317,700
Other receivables and current assets	249,619	216,113
Total current assets	1,555,480	1,311,177
Long-term assets:
Property and equipment, net	83,636	61,655
Operating lease right-of-use assets	105,671
Goodwill	2,413,280	1,572,455
Other intangible assets, net	476,711	211,272
Other long-term assets	180,032	82,775
Deferred income taxes	24,077	26,630
Total long-term assets	3,283,407	1,954,787
Total assets	4,838,887	3,265,964
Current liabilities:
Accounts payable	14,298	7,953
Accrued bonuses and commissions	101,546	79,945
Accrued income taxes	9,996	8,726
Current portion of long-term debt	75,000	0
Other accrued expenses and liabilities	142,947	99,559
Deferred revenue	351,353	328,584
Total current liabilities	695,140	524,767
Long-term liabilities:
Deferred income taxes	78,643	30,077
Long-term operating lease liabilities	91,768
Long-term debt	423,531	0
Other long-term liabilities	96,426	61,573
Total long-term liabilities	690,368	91,650
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; 94,627,585 and 93,236,023 shares issued, respectively	946	932
Additional paid-in capital	1,188,939	867,462
Retained earnings	3,370,706	2,919,411
Treasury stock, at cost: 8,893,177 and 9,601,670 shares, respectively	(1,041,831)	(1,075,879)
Accumulated other comprehensive loss	(65,381)	(62,379)
Total stockholders’ equity	3,453,379	2,649,547
Total liabilities and stockholders’ equity	$ 4,838,887	$ 3,265,964

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 8,700	$ 8,000
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	94,627,585	93,236,023
Treasury stock, shares	8,893,177	9,601,670

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenue:
Total revenue	$ 1,515,892	$ 1,293,636	$ 1,095,250
Cost of sales:
Amortization	21,710	27,034	36,794
Total cost of sales	166,273	155,885	150,164
Gross profit	1,349,619	1,137,751	945,086
Operating expenses:
Selling, general and administrative	521,200	413,580	338,640
Research and development	298,210	233,802	202,746
Amortization	15,169	13,795	12,972
Total operating expenses	834,579	661,177	554,358
Operating income	515,040	476,574	390,728
Interest income	12,796	11,419	6,962
Interest expense	(3,461)	(59)	(86)
Other expense, net	(1,792)	(849)	(1,910)
Income before income tax provision	522,583	487,085	395,694
Income tax provision	71,288	67,710	136,443
Net income	$ 451,295	$ 419,375	$ 259,251
Earnings per share – basic:
Earnings per share	$ 5.36	$ 4.99	$ 3.05
Weighted average shares	84,259	83,973	84,988
Earnings per share – diluted:
Earnings per share	$ 5.25	$ 4.88	$ 2.98
Weighted average shares	85,925	85,913	86,854
Software licenses
Revenue:
Total revenue	$ 699,630	$ 576,717	$ 624,964
Cost of sales:
Total cost of sales	23,944	18,619	34,421
Maintenance and service
Revenue:
Total revenue	816,262	716,919	470,286
Cost of sales:
Total cost of sales	$ 120,619	$ 110,232	$ 78,949

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Net income	$ 451,295	$ 419,375	$ 259,251
Other comprehensive (loss) income:
Foreign currency translation adjustments	(3,002)	(24,535)	19,808
Comprehensive income	$ 448,293	$ 394,840	$ 279,059

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities:
Net income	$ 451,295	$ 419,375	$ 259,251
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	60,516	59,255	67,678
Operating lease right-of-use assets amortization	18,459
Deferred income tax benefit	(14,511)	(33,675)	(2,693)
Provision for bad debts	2,928	1,577	1,474
Stock-based compensation expense	116,190	83,346	53,154
Other	2,778	410	21
Changes in operating assets and liabilities:
Accounts receivable	(154,403)	(74,455)	(14,406)
Other receivables and current assets	(26,182)	(30,241)	(18,498)
Other long-term assets	(5,622)	1,839	(435)
Accounts payable, accrued expenses and current liabilities	38,543	19,920	27,045
Accrued income taxes	575	1,086	1,215
Deferred revenue	17,245	56,213	20,648
Other long-term liabilities	(7,875)	(19,662)	33,206
Net cash provided by operating activities	499,936	484,988	427,660
Cash flows from investing activities:
Acquisitions, net of cash acquired	(787,196)	(283,026)	(63,885)
Capital expenditures	(44,940)	(21,762)	(19,149)
Other investing activities	(1,412)	(7,443)	(11,631)
Net cash used in investing activities	(833,548)	(312,231)	(94,665)
Cash flows from financing activities:
Proceeds from long-term debt	500,000	0	0
Purchase of treasury stock	(59,116)	(269,801)	(336,042)
Restricted stock withholding taxes paid in lieu of issued shares	(42,431)	(28,879)	(11,112)
Proceeds from shares issued for stock-based compensation	34,093	41,019	52,503
Other financing activities	(3,137)	(5,014)	0
Net cash provided by (used in) financing activities	429,409	(262,675)	(294,651)
Effect of exchange rate fluctuations on cash and cash equivalents	(842)	(14,444)	20,678
Net increase (decrease) in cash and cash equivalents	94,955	(104,362)	59,022
Cash and cash equivalents, beginning of period	777,139	881,501	822,479
Cash and cash equivalents, end of period	872,094	777,139	881,501
Supplemental disclosures of cash flow information:
Income taxes paid	86,770	87,244	116,389
Interest paid	787	114	199
Fair value of common stock issued as consideration in connection with acquisitions	$ 307,173	$ 0	$ 0

CONSOLIDATED STATEMENTS OF STOC

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)/Income
Beginning balance at Dec. 31, 2016	$ 2,208,405	$ 932	$ 883,010	$ 2,057,665	$ (675,550)	$ (57,652)
Beginning balance, shares at Dec. 31, 2016		93,236			7,548
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury shares acquired	$ (336,042)				$ (336,042)
Treasury shares acquired, shares	2,750				2,750
Stock-based compensation, activity			(9,653)
Stock-based compensation activity	$ 94,409				$ 104,062
Stock-based compensation activity, shares					(1,254)
Other comprehensive (loss)/income	19,808					19,808
Net income for the year	259,251			259,251
Ending balance at Dec. 31, 2017	2,245,831	$ 932	873,357	2,316,916	$ (907,530)	(37,844)
Ending balance, shares at Dec. 31, 2017		93,236			9,044
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury shares acquired	$ (269,801)				$ (269,801)
Treasury shares acquired, shares	1,674				1,674
Stock-based compensation, activity			(5,895)
Stock-based compensation activity	$ 95,557				$ 101,452
Stock-based compensation activity, shares					(1,116)
Other comprehensive (loss)/income	(24,535)					(24,535)
Net income for the year	419,375			419,375
Ending balance at Dec. 31, 2018	2,649,547	$ 932	867,462	2,919,411	$ (1,075,879)	(62,379)
Ending balance, shares at Dec. 31, 2018		93,236			9,602
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Acquisition of Livermore Software Technology, LLC	307,173	$ 14	307,159
Acquisition of Livermore Software Technology, LLC, shares		1,392
Treasury shares acquired	$ (59,116)				$ (59,116)
Treasury shares acquired, shares	330				330
Stock-based compensation, activity			14,318
Stock-based compensation activity	$ 107,482				$ 93,164
Stock-based compensation activity, shares					(1,039)
Other comprehensive (loss)/income	(3,002)					(3,002)
Net income for the year	451,295			451,295
Ending balance at Dec. 31, 2019	$ 3,453,379	$ 946	$ 1,188,939	$ 3,370,706	$ (1,041,831)	$ (65,381)
Ending balance, shares at Dec. 31, 2019		94,628			8,893

Organization

Organization	12 Months Ended
	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	Organization We develop and globally market engineering simulation software and services widely used by engineers, designers, researchers and students across a broad spectrum of industries and academia, including aerospace and defense, automotive, electronics, semiconductors, energy, materials and chemical processing, turbomachinery, consumer products, healthcare, and sports. As defined by the accounting guidance for segment reporting, we operate as one segment. Given the integrated approach to the multi-discipline problem-solving needs of our customers, a single sale of software may contain components from multiple product areas and include combined technologies. We also have 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 us to provide accurate historical or current reporting among our various product lines.

Accounting Policies

Accounting Policies	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Accounting Policies	Accounting Policies Accounting Principles The financial statements and accompanying notes are prepared in accordance with accounting principles generally accepted in the United States. Certain items in the consolidated financial statements and the notes to the consolidated financial statements of prior years have been reclassified to conform to the current year's presentation. These reclassifications had no effect on reported net income, comprehensive income, cash flows, total assets or total liabilities and stockholders' equity. Principles of Consolidation The accompanying consolidated financial statements include our accounts and those of our wholly owned subsidiaries. All intercompany accounts and transactions have been eliminated. Recently Adopted Accounting Guidance Leases: In February 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2016-02, Leases (Topic 842) (ASU 2016-02). We adopted ASU 2016-02 and its related amendments (collectively known as Accounting Standards Codification (ASC) 842) on January 1, 2019 using the modified retrospective approach. Results for reporting periods beginning after January 1, 2019 are presented under ASC 842, while prior period amounts are not adjusted and continue to be reported in accordance with ASC 840, Leases . ASC 842 requires virtually all leases, other than leases of intangible assets, to be recorded on the balance sheet with a right-of-use (ROU) asset and a corresponding lease liability. We elected the package of practical expedients permitted under the transition guidance within the new standard, which allowed us to carry forward our historical assessments of whether a contract contains a lease, lease classification and initial direct costs. In addition, we elected the accounting policy to combine the lease and nonlease components as a single component for all asset classes. We determine if an arrangement is a lease at inception. Leases are classified as either operating or finance leases based on certain criteria. This classification determines the timing and presentation of expenses on the income statement, as well as the presentation of the related cash flows and balance sheet. Operating leases are recorded on the balance sheet as operating lease right-of-use assets, other accrued expenses and liabilities, and long-term operating lease liabilities. We currently have no finance leases. ROU assets and related liabilities are recorded at lease commencement based on the present value of the lease payments over the expected lease term. Lease payments include future increases unless the increases are based on changes in an index or rate. As our leases do not usually provide an implicit rate, our incremental borrowing rate is used to calculate ROU assets and related liabilities. The incremental borrowing rate is determined based on our estimated credit rating, the term of the lease, the economic environment where the asset resides and full collateralization. The ROU assets and related lease liabilities include optional renewals for which we are reasonably certain to exercise; whereas, optional terminations are included unless it is reasonably certain not to be elected. The adoption of the new standard resulted in the recognition of ROU assets of $90.9 million and lease liabilities of $92.5 million , and corresponding deferred tax assets and liabilities, on our consolidated balance sheet as of January 1, 2019. The adoption had no impact on our consolidated statements of income or cash flows. Implementation cost accounting for cloud computing arrangements: In August 2018, the FASB issued ASU No. 2018-15, Intangibles—Goodwill and Other—Internal-Use Software (Subtopic 350-40): Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract (ASU 2018-15). The standard aligns the accounting for costs incurred to implement a cloud computing arrangement (CCA) that is a service arrangement with the guidance on capitalizing costs associated with developing or obtaining internal-use software. Under ASU 2018-15, an entity would apply Subtopic 350-40 to determine which implementation costs related to a CCA that is a service contract should be capitalized. The standard does not change the accounting for the service component of a CCA. The associated cash flows will be reflected within operating activities. We retrospectively adopted the guidance during the quarter ended December 31, 2019. The adoption resulted in the reclassification of cash flows associated with implementation costs related to CCAs that are service contracts on our consolidated statements of cash flows. This resulted in a decrease to operating cash flows, and a corresponding increase to investing cash flows, of $2.5 million , $1.4 million and $2.8 million for the years ending December 31, 2019, 2018 and 2017, respectively. The adoption had no impact on our consolidated balance sheets or consolidated statements of income. Accounting Guidance Issued and Not Yet Adopted Credit losses: In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (ASU 2016-13). The current guidance requires the allowance for doubtful accounts to be estimated based on an incurred loss model, which considers past and current conditions. ASU 2016-13 requires companies to use an expected loss model that also considers reasonable and supportable forecasts of future conditions. ASU 2016-13 is effective for annual periods beginning after December 15, 2019, including interim periods within that reporting period. Early adoption is permitted for annual periods beginning after December 15, 2018, including interim periods within that reporting period. The standard requires a cumulative-effect adjustment to the balance sheet as of the beginning of the first reporting period in which the guidance is effective. We will adopt the standard effective January 1, 2020 and do not expect the adoption of the new standard to have a material effect on our consolidated financial statements. Income taxes: In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes (ASU 2019-12), as part of its initiative to reduce complexity in the accounting standards. The amendments in ASU 2019-12 eliminate certain exceptions related to the approach for intraperiod tax allocation, the methodology for calculating income taxes in an interim period and the recognition of deferred tax liabilities for outside basis differences. ASU 2019-12 also clarifies and simplifies other aspects of the accounting for income taxes. ASU 2019-12 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020. Early adoption is permitted, including adoption in any interim period. We are currently evaluating the impact that this guidance will have upon our financial position and results of operations, if any. 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, including those related to the Tax Cuts and Jobs Act • Uncertain tax positions • Tax valuation reserves • Fair value of stock-based compensation and probabilities of performance award attainment • Contract revenue • Standalone selling prices of our products and services • Acquired deferred revenue • Useful lives for depreciation and amortization • Valuations of goodwill and other intangible assets • Deferred compensation • Loss contingencies • Operating lease assets and liabilities 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 Our revenue is derived principally from the licensing of computer software products and from related maintenance contracts. We adopted ASC 606 on January 1, 2018. ASC 606 requires an entity to evaluate revenue recognition by identifying a contract with a customer, identifying the performance obligations in the contract, determining the transaction price, allocating the transaction price to the performance obligations in the contract, and recognizing revenue when (or as) the entity satisfies a performance obligation. Revenue Recognition Policy 2019 and 2018 (ASC 606) We enter into contracts that include combinations of products, maintenance and services, which are accounted for as separate performance obligations with differing revenue recognition patterns. Revenue from perpetual licenses is classified as software license revenue. Software license revenue is recognized up front upon delivery of the licensed product and/or the utility that enables the customer to access authorization keys, provided that an enforceable contract has been received. Typically, our perpetual licenses are sold with post-contract support (PCS), which includes unspecified technical enhancements and customer support. We allocate value in bundled perpetual and PCS arrangements based on the standalone selling prices of the perpetual license and PCS. Revenue from PCS is classified as maintenance revenue and is recognized ratably over the term of the contract, as we satisfy the PCS performance obligation over time. In addition to perpetual licenses, we sell time-based lease licenses. Lease licenses are sold only as a bundled arrangement that includes the rights to a term software license and PCS. Utilizing observable inputs, we determined that 50% of the estimated standalone selling price of the lease license is attributable to the term license and 50% is attributable to the PCS. This determination considered the value relationship for our products between PCS to time-based lease licenses, the value relationship between PCS and perpetual licenses, the average economic life of our products, software renewal rates and the price of the bundled arrangement in relation to the perpetual licensing approach. Consistent with the perpetual sales, the license component is classified as software license revenue and recognized as revenue up front at the commencement of the lease upon delivery of the licensed product and/or utility that enables the customer to access authorization keys. The PCS is classified as maintenance revenue and is recognized ratably over the term of the contract, as we satisfy the PCS performance obligation over time. Revenue from training, support and other services is recognized as the services are performed. For contracts in which the service consists of a single performance obligation, such as providing a training class to a customer, we recognize revenue upon completion of the performance obligation. For service contracts that are longer in duration and often include multiple performance obligations (for example, both training and consulting), we measure the progress toward completion of the obligations and recognize revenue accordingly. In measuring progress towards the completion of performance obligations, we typically utilize output-based estimates for services with contractual billing arrangements that are not based on time and materials, and estimate 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. Proceeds from customers for the purpose of expediting road-map items, developing new products or creating specific features and functionality for existing products is classified as revenue. We also execute arrangements through independent channel partners in which the channel partners are authorized to market and distribute our software products to end users of our 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. We recognize revenue from transactions with channel partners in a manner consistent with the direct sales described above for both perpetual and time-based licenses. Revenue from channel partner transactions is the amount remitted to us by the channel partners. This amount includes a fee for PCS that is compensation for providing technical enhancements and the second level of technical support to the end user, which is recognized over the period that PCS is to be provided. 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. We do not offer right of return. We warrant to our customers that our software will perform substantially as specified in our current user manuals. We have not experienced significant claims related to software warranties beyond the scope of maintenance support, which we are already obligated to provide. The warranty is not sold, and cannot be purchased, separately. The warranty does not provide any type of additional service to the customer or performance obligation for us. Our agreements with our customers generally require us to indemnify the customer against claims that our software infringes third-party patent, copyright, trademark or other proprietary rights. Such indemnification obligations are generally limited in a variety of industry-standard respects, including our right to replace an infringing product. Significant Judgments (ASC 606) Our contracts with customers typically include promises to transfer licenses and services to a customer. Judgment is required to determine if the promises are separate performance obligations, and if so, to allocate the transaction price to each performance obligation. We use the estimated standalone selling price method to allocate the transaction price for each performance obligation. The estimated standalone selling price is determined using all information reasonably available to us, including market conditions and other observable inputs. The corresponding revenues are recognized as the related performance obligations are satisfied. We apply a practical expedient to expense sales commissions as incurred when the amortization period would have been one year or less. Sales commissions associated with the initial year of multi-year contracts are expensed as incurred due to their immateriality. Sales commissions associated with multi-year contracts beyond the initial year are subject to an employee service requirement and are expensed as incurred as they are not considered incremental costs to obtain a contract. We are required to adjust promised amounts of consideration for the effects of the time value of money if the timing of the payments provides the customer or us with a significant financing benefit. We consider various factors in assessing whether a financing component exists, including the duration of the contract, market interest rates and the timing of payments. Our contracts do not include a significant financing component requiring adjustment to the transaction price. Revenue Recognition Policy 2017 (ASC 605) Revenue from perpetual licenses was classified as license revenue and was recognized upon delivery of the licensed product and/or the utility that enabled the customer to access authorization keys, provided that acceptance had occurred and a signed contractual obligation was received, the price was fixed and determinable, and collectibility of the receivable was probable. We determined the fair value of PCS sold together with perpetual licenses based on the rate charged for PCS when sold separately. Revenue from PCS contracts was classified as maintenance and service revenue and was recognized ratably over the term of the contract. Revenue for software lease licenses was classified as license revenue and was recognized over the period of the lease contract. Typically, our software leases include PCS which, due to the short term (principally one year or less) of our software lease licenses, were not permitted to be separated from lease revenue for accounting purposes. As a result, both the lease licenses and PCS were recognized ratably over the lease period. We included the revenue for the entire lease arrangement within software license revenue in the consolidated statements of income. Many of our semiconductor products are typically licensed via longer term leases of 24 – 36 months. We recognized revenue for these licenses over the term of the lease contract. Because we did not have vendor-specific objective evidence of the fair value of these leases, we also recognized 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 was recognized as the services were performed. We applied the specific performance method to contracts in which the service consisted of a single act, such as providing a training class to a customer, and the proportional performance method to other service contracts that were longer in duration and often included multiple acts (for example, both training and consulting). In applying the proportional performance method, we typically utilized output-based estimates for services with contractual billing arrangements that were not based on time and materials, and estimated output based on the total tasks completed as compared to the total tasks required for each work contract. Input-based estimates were utilized for services that involved general consultations with contractual billing arrangements based on time and materials, utilizing direct labor as the input measure. The accounting treatment under ASC 605 associated with arrangements through independent channel partners, non-income related taxes, warranties and indemnification obligations is consistent with the accounting treatment under ASC 606 described above. Cash and Cash Equivalents Cash and cash equivalents consist primarily of highly liquid investments such as deposits held at major banks and money market funds. Cash equivalents are carried at cost, which approximates fair value. Our cash and cash equivalents balances comprise the following: December 31, 2019 December 31, 2018 (in thousands, except percentages) Amount % of Total Amount % of Total Cash accounts $ 549,639 63.0 $ 331,084 42.6 Money market funds 322,455 37.0 446,055 57.4 Total $ 872,094 $ 777,139 Our 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 year 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 are expensed as incurred. Internally developed software costs required to be capitalized as defined by the accounting guidance are not material to our consolidated financial statements. Business Combinations When we consummate 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 acquisition date fair value of the net identifiable assets acquired. 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, our 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, we record adjustments to the assets acquired and liabilities assumed with the corresponding offset to goodwill as we obtain 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 fair value of 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 range from two years to seventeen years . Amortization expense for intangible assets was $36.9 million , $40.8 million and $49.8 million for the years ended December 31, 2019 , 2018 and 2017 , respectively. We test 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. We have one reporting unit. Goodwill is tested at this reporting unit level and indefinite-lived intangible assets are tested at the individual asset level. This requires us 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. We perform our annual impairment tests for goodwill and indefinite-lived intangible assets as of January 1 of each year unless there is an indicator that would require a test during the year. We periodically review 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 We have 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 our products. We perform periodic credit evaluations of our customers' financial condition and generally do not require collateral. The following table outlines concentrations of risk with respect to our revenue: Year Ended December 31, (as a % of revenue) 2019 2018 2017 Revenue from channel partners 23 % 22 % 25 % Largest channel partner 4 % 4 % 5 % 2 nd largest channel partner 2 % 2 % 2 % No single customer accounted for more than 5% of our revenue in 2019 , 2018 or 2017 . In addition to the concentration of credit risk with respect to trade receivables, our cash and cash equivalents are also exposed to concentration risk. Our cash and cash equivalent accounts are insured through various public and private bank deposit insurance programs, foreign and domestic; however, a significant portion of our funds are not insured. The following table outlines concentrations of risk with respect to our cash and cash equivalents: As of December 31, (in thousands) 2019 2018 Cash and cash equivalents held domestically $ 626,433 $ 616,249 Cash and cash equivalents held by foreign subsidiaries 245,661 160,890 Cash and cash equivalents held in excess of deposit insurance, foreign and domestic 855,721 754,163 Largest balance of cash and cash equivalents held with one financial institution, foreign and domestic 330,551 452,166 Allowance for Doubtful Accounts We make judgments as to our ability to collect outstanding receivables and provide 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, we consider our historical collection experience and current economic trends in the customer's industry and geographic region. We recorded provisions for bad debts of $2.9 million , $1.6 million and $1.5 million for the years ended December 31, 2019, 2018 and 2017, respectively. Income Taxes We account 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. We record net deferred tax assets to the extent we believe these assets will more likely than not be realized. In making such determination, we consider 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 we determine that we 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 its examination even though the statute of limitations remains open. We recognize interest and penalties related to income taxes within the income tax expense line in the 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 our 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 our functional currency or our subsidiaries' functional currencies are translated at the effective exchange rate on the balance sheet date. Gains and losses resulting from foreign exchange transactions are included in other expense, net. We recorded net foreign exchange losses of $2.5 million , $3.1 million and $1.9 million for the years ended December 31, 2019 , 2018 and 2017, respectively. The financial statements of our 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 awards 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) 2019 2018 2017 Net income $ 451,295 $ 419,375 $ 259,251 Weighted average shares outstanding – basic 84,259 83,973 84,988 Dilutive effect of stock plans 1,666 1,940 1,866 Weighted average shares outstanding – diluted 85,925 85,913 86,854 Basic earnings per share $ 5.36 $ 4.99 $ 3.05 Diluted earnings per share $ 5.25 $ 4.88 $ 2.98 Anti-dilutive shares 14 7 84 Stock-Based Compensation We account 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 services in exchange for the award, typically the vesting period. Fair Value of Financial Instruments We account 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.

Revenue from Contracts with Cus

Revenue from Contracts with Customers	12 Months Ended
	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Revenue from Contracts with Customers	Revenue from Contracts with Customers Adoption of ASC 606, Revenue from Contracts with Customers We adopted ASC 606 on January 1, 2018 using the modified retrospective approach for all contracts not completed as of the date of adoption. Results for reporting periods beginning after January 1, 2018 are presented under ASC 606, while prior period amounts are not adjusted and continue to be reported in accordance with ASC 605. The adoption of ASC 606 represents a change in accounting principle that will more closely align revenue recognition with the delivery of our software licenses, maintenance and services. We recorded an increase to retained earnings of $242.4 million , or $183.1 million net of tax, on January 1, 2018 due to the cumulative effect of the ASC 606 adoption, with the impact primarily derived from revenue related to time-based software lease licenses. Software lease license revenue was recognized ratably over the term of the contract under the previous guidance; however, approximately 50% of the contract is recognized up front at the commencement of the lease under ASC 606 with the remainder recognized ratably to maintenance and service revenue. Disaggregation of Revenue The following table summarizes revenue: Year Ended December 31, (in thousands) 2019 2018 2017 Revenue: Lease licenses $ 406,043 $ 275,619 $ 376,886 Perpetual licenses 293,587 301,098 248,078 Software licenses 699,630 576,717 624,964 Maintenance 760,574 676,883 440,428 Service 55,688 40,036 29,858 Maintenance and service 816,262 716,919 470,286 Total revenue $ 1,515,892 $ 1,293,636 $ 1,095,250 Direct revenue, as a percentage of total revenue 77.1 % 77.6 % 75.2 % Indirect revenue, as a percentage of total revenue 22.9 % 22.4 % 24.8 % Our software licenses revenue is recognized up front, while maintenance and service revenue is generally recognized over the term of the contract. Deferred Revenue Deferred revenue consists of billings made or payments received in advance of revenue recognition from customer agreements. The timing of revenue recognition may differ from the timing of billings to customers. Payment terms vary by the type and location of customer and the products or services offered. The time between invoicing and when payment is due is not significant. The changes in deferred revenue, inclusive of both current and long-term deferred revenue, during the years ended December 31, 2019 and 2018 were as follows: (in thousands) 2019 2018 Beginning balance – January 1 $ 343,174 $ 299,730 Acquired deferred revenue 6,880 2,470 Deferral of revenue 1,532,549 1,339,964 Recognition of deferred revenue (1,515,892 ) (1,293,636 ) Currency translation (1,437 ) (5,354 ) Ending balance – December 31 $ 365,274 $ 343,174 Revenue allocated to remaining performance obligations represents contracted revenue that has not yet been recognized, which includes both deferred revenue and backlog. Our backlog represents installment billings for periods beyond the current quarterly billing cycle. Revenue recognized during the years ended December 31, 2019 and 2018 included amounts in deferred revenue and backlog at the beginning of the period of $475.9 million and $387.2 million , respectively. Total revenue allocated to remaining performance obligations as of December 31, 2019 will be recognized as revenue as follows: (in thousands) Next 12 months $ 569,751 Months 13-24 177,364 Months 25-36 93,097 Thereafter 30,531 Total revenue allocated to remaining performance obligations $ 870,743

Acquisitions

Acquisitions	12 Months Ended
	Dec. 31, 2019
Business Combinations [Abstract]
Acquisitions	Acquisitions 2019 Acquisitions On November 1, 2019, we completed the acquisition of 100% of the shares of LST, the premier provider of explicit dynamics and other advanced finite element analysis technology. The acquisition empowers our customers to solve a new class of engineering challenges, including developing safer automobiles, aircraft and trains while reducing or even eliminating the need for costly physical testing. The transaction closed with a purchase price of $777.8 million , which included $470.6 million in cash and the issuance of 1.4 million shares of our common stock in an unregistered offering to the prior owners of LST. The fair value of the common stock issued as consideration was based on the volume-weighted average price of our common stock on November 1, 2019 of $220.74 , resulting in a fair value of $307.2 million . On February 1, 2019, we completed the acquisition of 100% of the shares of Granta Design for a purchase price of $208.7 million , paid in cash and inclusive of final net working capital adjustments. The acquisition of Granta Design, the premier provider of materials information technology, expands our portfolio into this important area, giving customers access to materials intelligence, including data that is critical to successful simulations. Additionally, during the year ended December 31, 2019 , we acquired Dynardo, Helic and DfR Solutions to combine the acquired technologies with our existing comprehensive multiphysics portfolio. These acquisitions were not individually significant. The combined purchase price of these other acquisitions was $136.2 million , paid in cash. During the year ended December 31, 2019 , we incurred $6.6 million in acquisition-related expenses, recognized as selling, general and administrative expense on the consolidated statements of income. The assets and liabilities of the acquisitions have been recorded based upon management's estimates of their fair market values as of each respective date of acquisition. The following tables summarize the fair values of consideration transferred and the fair values of identified assets acquired and liabilities assumed at each respective date of acquisition: Fair Value of Consideration Transferred: (in thousands) LST Granta Design Other Acquisitions Total Cash $ 470,623 $ 208,736 $ 136,232 $ 815,591 Ansys common stock 307,173 — — 307,173 Total consideration transferred at fair value $ 777,796 $ 208,736 $ 136,232 $ 1,122,764 Recognized Amounts of Identifiable Assets Acquired and Liabilities Assumed: (in thousands) LST Granta Design Other Acquisitions Total Cash $ 8,520 $ 13,644 $ 6,231 $ 28,395 Accounts receivable and other tangible assets 20,568 6,941 10,746 38,255 Developed software and core technologies (10-year weighted-average life) 167,700 32,445 25,018 225,163 Customer lists (15-year weighted-average life) 25,900 20,016 15,743 61,659 Trade names (10-year weighted-average life) 10,600 4,579 2,051 17,230 Indemnification asset 34,039 — — 34,039 Accounts payable and other liabilities (3,721 ) (6,714 ) (6,425 ) (16,860 ) Deferred revenue (3,565 ) (1,426 ) (1,889 ) (6,880 ) Uncertain tax positions (34,039 ) — (257 ) (34,296 ) Net deferred tax liabilities (47,596 ) (9,822 ) (8,294 ) (65,712 ) Total identifiable net assets $ 178,406 $ 59,663 $ 42,924 $ 280,993 Goodwill $ 599,390 $ 149,073 $ 93,308 $ 841,771 LST has uncertain tax positions inclusive of interest and penalties of $34.0 million and a corresponding indemnification asset. The uncertain tax positions reflect potential federal and state tax liabilities associated with tax years 2016 to 2019. Settlements of the tax positions, if any, will be funded by the indemnification asset that was created in accordance with the executed Agreement and Plan of Merger. The goodwill, which is generally 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 acquisitions. The fair values of the assets acquired and liabilities assumed are based on preliminary calculations. The estimates and assumptions for these items are subject to change as additional information about what was known and knowable at the acquisition date is obtained during the measurement period (up to one year from the acquisition date). We determined the fair value of our intangible assets using various valuation techniques, including the relief-from-royalty method and the multi-period excess earnings method. These models utilize certain unobservable inputs classified as Level 3 measurements as defined by ASC 820, Fair Value Measurements and Disclosures . The determination of fair value requires considerable judgment and is sensitive to changes in underlying assumptions, estimates and market factors. Estimating fair value requires us to make assumptions and estimates regarding our future plans, as well as industry and economic conditions. These assumptions and estimates include, but are not limited to: royalty rate, discount rate and attrition rate. The valuation method and assumptions used to determine the fair value of the significant intangible assets acquired in 2019 are as follows: Intangible Asset Valuation Method LST Assumptions Granta Design Assumptions Developed software and core technologies Relief-from-royalty Royalty rate: 50% Discount rate: 10% Royalty rate: 8% - 10% Discount rate: 12.5% Trade names Relief-from-royalty Royalty rate: 2% Discount rate: 10% Royalty rate: 2% Discount rate: 14% Customer lists Multi-period excess earnings Attrition rate: 10% Discount rate: 11% Attrition rate: 10% Discount rate: 12.5% The operating results of each acquisition have been included in our consolidated financial statements since each respective date of acquisition. The effects of the business combinations were not material to our consolidated results of operations individually. The table presented below reflects the aggregate impact on our results of operations of the 2019 acquisitions from the date of acquisition to December 31, 2019. The operating income does not include integration costs borne directly by us and our non-acquired subsidiaries as a result of the acquisitions. (in thousands) Year Ended December 31, 2019 Revenue $ 44,079 Operating income $ 6,733 2018 Acquisition On May 2, 2018, we completed the acquisition of 100% of the shares of OPTIS, a premier provider of software for scientific simulation of light, human vision and physics-based visualization, for a purchase price of $291.0 million , paid in cash. The acquisition extends our portfolio into the area of optical simulation to provide comprehensive sensor solutions, covering visible and infrared light, electromagnetics and acoustics for camera, radar and lidar. The operating results of OPTIS have been included in our consolidated financial statements since May 2, 2018, the date of acquisition. The assets and liabilities of OPTIS have been recorded based upon management's estimates of their fair market values as of the acquisition date. The following tables summarize the fair value of consideration transferred and the fair values of identified assets acquired and liabilities assumed at the acquisition date: Fair Value of Consideration Transferred: (in thousands) OPTIS Cash $ 290,983 Recognized Amounts of Identifiable Assets Acquired and Liabilities Assumed: (in thousands) OPTIS Cash $ 7,957 Accounts receivable and other tangible assets 15,910 Developed software and core technologies (10-year weighted-average life) 47,597 Customer lists (12-year life) 41,303 Trade names (9-year weighted-average life) 10,749 Accounts payable and other liabilities (11,941 ) Deferred revenue (2,470 ) Net deferred tax liabilities (23,438 ) Total identifiable net assets $ 85,667 Goodwill $ 205,316 The goodwill, which is generally not tax-deductible, is attributed to intangible assets that do not qualify for separate recognition, including the assembled workforce of the acquired business and the synergies expected to arise as a result of the acquisition of OPTIS. During the one-year measurement period since the OPTIS acquisition date, we adjusted the fair values of the assets acquired and liabilities assumed, with the offset recorded as a $2.6 million increase to goodwill. These adjustments were made as we 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. Full pro forma results of operations have not been presented as the effects of the OPTIS business combination were not material to our consolidated results of operations. The table presented below reflects the impact of OPTIS from the date of acquisition to December 31, 2018. The operating loss does not include integration costs borne directly by us and our non-OPTIS subsidiaries as a result of the acquisition. (in thousands) Year Ended December 31, 2018 Revenue $ 18,532 Operating loss $ (5,462 ) 2017 Acquisitions During the year ended December 31, 2017 , we completed various acquisitions to expand our customer base and 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 price of the acquisitions was approximately $67.0 million . The 2017 technology acquisitions are further described in the table below: Date of Closing Company Details November 15, 2017 3DSIM 3DSIM, a developer of premier additive manufacturing technology, gives us a complete additive manufacturing simulation workflow solution. 3DSIM's software solutions empower manufacturers, designers, materials scientists and engineers to achieve their objectives through simulation-driven innovation rather than physical trial and error. July 5, 2017 Computational Engineering International, Inc. (CEI Inc.) CEI Inc., the developer of EnSight, aids engineers and scientists in their ability to analyze, visualize and communicate large simulation data sets in clear, higher-resolution outputs. March 10, 2017 CLK Design Automation (CLK-DA) CLK-DA offers fast transistor simulation technology that complements our semiconductor product portfolio. The operating results of each acquisition have been included in our consolidated financial statements since each respective date of acquisition. The effects of the business combinations were not material to our consolidated results of operations individually or in the aggregate.

Other Receivables and Current A

Other Receivables and Current Assets and Other Accrued Expenses and Liabilities	12 Months Ended
	Dec. 31, 2019
Other Receivables and Current Assets and Other Accrued Expenses and Liabilities [Abstract]
Other Receivables and Current Assets and Other Accrued Expenses and Liabilities	Other Receivables and Current Assets and Other Accrued Expenses and Liabilities Our other receivables and current assets, and other accrued expenses and liabilities, comprise the following balances: December 31, (in thousands) 2019 2018 Receivables related to unrecognized revenue $ 177,679 $ 167,144 Income taxes receivable, including overpayments and refunds 26,672 13,709 Prepaid expenses and other current assets 45,268 35,260 Total other receivables and current assets $ 249,619 $ 216,113 Consumption, sales and VAT tax liabilities $ 36,398 $ 24,192 Accrued expenses and other current liabilities 106,549 75,367 Total other accrued expenses and liabilities $ 142,947 $ 99,559 Receivables related to unrecognized revenue represent the current portion of billings made for customer contracts that have not yet been recognized as revenue.

Property and Equipment

Property and Equipment	12 Months Ended
	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Property and Equipment	Property and Equipment Property and equipment consists of the following: December 31, (in thousands) Estimated Useful Lives 2019 2018 Equipment 1-15 years $ 105,428 $ 92,409 Computer software 1-5 years 33,878 35,053 Buildings and improvements 5-40 years 38,095 27,352 Leasehold improvements 1-17 years 19,876 15,782 Furniture 1-13 years 12,766 10,846 Land 2,696 1,759 Property and equipment, gross 212,739 183,201 Less: Accumulated depreciation (129,103 ) (121,546 ) Property and equipment, net $ 83,636 $ 61,655 Depreciation expense related to property and equipment was $23.6 million , $18.4 million and $17.9 million for the years ended December 31, 2019 , 2018 and 2017 , respectively.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	12 Months Ended
	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	Goodwill and Intangible Assets Goodwill represents the excess of the fair value of consideration transferred over the fair value of net identifiable assets acquired. Identifiable intangible assets acquired in business combinations are recorded based on their fair values on the date of acquisition. During the first quarter of 2019 , we 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, 2019 . No other events or circumstances changed during the year ended December 31, 2019 that would indicate that the fair values of our reporting unit and indefinite-lived intangible asset are below their carrying values. Intangible assets are classified as follows: December 31, 2019 December 31, 2018 (in thousands) Gross Carrying Amount Accumulated Amortization Gross Carrying Amount Accumulated Amortization Finite-lived intangible assets: Developed software and core technologies $ 635,063 $ (332,622 ) $ 410,680 $ (314,730 ) Customer lists and contract backlog 269,629 (132,596 ) 209,031 (117,614 ) Trade names 154,259 (117,379 ) 137,225 (113,677 ) Total $ 1,058,951 $ (582,597 ) $ 756,936 $ (546,021 ) Indefinite-lived intangible asset: Trade name $ 357 $ 357 Finite-lived intangible assets are amortized over their estimated useful lives of two years to seventeen years . Amortization expense for the intangible assets reflected above was $36.9 million , $40.8 million and $49.8 million for the years ended December 31, 2019 , 2018 and 2017 , respectively. As of December 31, 2019 , estimated future amortization expense for the intangible assets reflected above is as follows: (in thousands) 2020 $ 54,735 2021 53,231 2022 53,548 2023 52,474 2024 50,530 Thereafter 211,836 Total intangible assets subject to amortization, net 476,354 Indefinite-lived trade name 357 Other intangible assets, net $ 476,711 The changes in goodwill during the years ended December 31, 2019 and 2018 were as follows: (in thousands) 2019 2018 Beginning balance - January 1 $ 1,572,455 $ 1,378,553 Acquisitions and adjustments (1) 842,588 204,381 Currency translation (1,763 ) (10,479 ) Ending balance - December 31 $ 2,413,280 $ 1,572,455 (1) In accordance with the accounting for business combinations, we 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 we obtained new information about facts and circumstances that existed as of the acquisition date that, if known, would have affected the measurement of the amounts recognized as of that date.

Fair Value Measurement

Fair Value Measurement	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurement	Fair Value Measurement The valuation hierarchy for disclosure of assets and liabilities reported at fair value prioritizes the inputs for such valuations into three broad levels: • Level 1: quoted prices (unadjusted) in active markets for identical assets or liabilities; • Level 2: quoted prices for similar assets and liabilities in active markets or inputs that are observable for the asset or liability, either directly or indirectly through market corroboration, for substantially the full term of the financial instrument; or • Level 3: unobservable inputs based on our own assumptions used to measure assets and liabilities at fair value. A financial asset's or liability's classification within the hierarchy is determined based on the lowest level input that is significant to the fair value measurement. The following tables provide the assets carried at fair value and measured on a recurring basis: Fair Value Measurements at Reporting Date Using: (in thousands) December 31, 2019 Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets Cash equivalents $ 322,455 $ 322,455 $ — $ — Short-term investments $ 288 $ — $ 288 $ — Deferred compensation plan investments $ 1,110 $ 1,110 $ — $ — Fair Value Measurements at Reporting Date Using: (in thousands) December 31, 2018 Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets Cash equivalents $ 446,055 $ 446,055 $ — $ — Short-term investments $ 225 $ — $ 225 $ — Deferred compensation plan investments $ 1,646 $ 1,646 $ — $ — The cash equivalents in the preceding tables represent money market funds, valued at net asset value, with carrying values which approximate their fair values because of their short-term nature. The short-term investments in the preceding tables represent deposits held by certain foreign subsidiaries. The deposits have fixed interest rates with original maturities ranging from three months to one year. The deferred compensation plan investments in the preceding tables represent trading securities held in a rabbi trust for the benefit of the non-employee Directors. These securities consist of mutual funds traded in an active market with quoted prices. As a result, the plan assets are classified as Level 1 in the fair value hierarchy. The plan assets are recorded within other long-term assets on our consolidated balance sheets.

Leases

Leases	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Leases	Leases We primarily have operating leases for office space and leased cars included in our ROU assets and lease liabilities. Our 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 term of the lease is 183 months, which began on October 1, 2014 and expires on December 31, 2029. The lease agreement includes options to renew the contract through August 2044, an option to lease additional space in January 2025 and an option to terminate the lease in December 2025. No options are included in the lease liability as renewal is not reasonably certain. In addition, we are reasonably certain we will not terminate the lease agreement. Absent the exercise of options in the lease, our base rent (inclusive of property taxes and certain operating costs) was $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 components of our global lease cost reflected in the consolidated statements of income for the year ended December 31, 2019 are as follows: (in thousands) Lease liability cost $ 22,507 Variable lease cost not included in the lease liability (1) 3,754 Total lease cost $ 26,261 (1) Variable lease cost includes common area maintenance, property taxes, utilities and fluctuations in rent due to a change in an index or rate. For the years ended December 31, 2018 and 2017, lease cost totaled $21.3 million and $18.4 million , respectively. Other information related to operating leases for the year ended December 31, 2019 is as follows: (in thousands) Cash paid for amounts included in the measurement of the lease liability: Operating cash flows from operating leases $ (20,031 ) Right-of-use assets obtained in exchange for new operating lease liabilities $ 35,191 As of December 31, 2019 , the weighted-average remaining lease term of operating leases was 7.7 years , and the weighted-average discount rate of operating leases was 3.7% . The maturity schedule of the operating lease liabilities as of December 31, 2019 is as follows: (in thousands) 2020 $ 21,617 2021 19,439 2022 16,616 2023 12,513 2024 12,421 Thereafter 46,159 Total future lease payments 128,765 Less: Present value adjustment (18,838 ) Present value of future lease payments (1) $ 109,927 (1) Includes the current portion of operating lease liabilities of $18.2 million , which is reflected in other accrued expenses and liabilities in the consolidated balance sheets. As of December 31, 2019 , we had operating office leases that have not yet commenced with combined lease obligations of $16.3 million . The leases commence in 2020 and have a weighted-average lease term of 7.2 years . The future minimum lease payments under ASC 840, including termination fees, under noncancellable operating leases for office space in effect at December 31, 2018 were as follows: (in thousands) 2019 $ 16,354 2020 12,469 2021 10,177 2022 8,523 2023 6,809 Thereafter 14,267 Total $ 68,599

Debt

Debt	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Debt	Debt In February 2019, we entered into a credit agreement for a $500.0 million unsecured revolving credit facility, which includes a $50.0 million sublimit for the issuance of letters of credit, with Bank of America, N.A. as the Administrative Agent. The revolving credit facility becomes payable in full on February 22, 2024 and is available for general corporate purposes, including, among others, to finance acquisitions and capital expenditures. In connection with the acquisition of LST, we amended our existing credit agreement (amended credit agreement). The amendment provides for a new $500.0 million unsecured term loan facility to finance the acquisition. The term loan was funded on November 1, 2019 and matures on November 1, 2024. Principal on the term loan will be payable on the last business day of each fiscal quarter commencing with the ninth full fiscal quarter after the funding date at a rate of 1.25% per quarter, increasing to 2.50% per quarter after the next four fiscal quarters. Borrowings under the amended credit agreement will accrue interest at the Eurodollar rate plus an applicable margin or at the base rate, at our election. For the quarter ended December 31, 2019 , we elected to apply the Eurodollar rate. The base rate is the applicable margin plus the highest of (i) the federal funds rate plus 0.500% , (ii) the Bank of America prime rate and (iii) the Eurodollar rate plus 1.000% . The applicable margin for these borrowings is a percentage per annum based on the lower of (1) a pricing level determined by our then-current consolidated leverage ratio and (2) a pricing level determined by our debt ratings (if such debt ratings exist). This results in a margin ranging from 1.125% to 1.750% and 0.125% to 0.750% for the Eurodollar rate and base rate, respectively. The interest rate in effect as of December 31, 2019 was 2.964% . The amended credit agreement contains language in the event the Eurodollar rate is not available due to LIBOR changes. If this occurs, the base rate will be used for borrowings. However, we may work with the Administrative Agent to amend the agreement to replace the Eurodollar rate with (i) one or more rates based on the Secured Overnight Financing Rate (SOFR); or (ii) another alternative benchmark rate, subject to the lenders' approval. The amended credit agreement contains customary representations and warranties, affirmative and negative covenants and events of default. The amended credit agreement also contains a financial covenant requiring us to maintain a consolidated leverage ratio of indebtedness to earnings before interest, taxes, depreciation and amortization not exceeding 3.50 to 1.00 as of the end of any fiscal quarter (for the four-quarter period ending on such date) with an opportunity for a temporary increase in such consolidated leverage ratio to 4.00 to 1.00 upon the consummation of certain qualified acquisitions for which the aggregate consideration is at least $250.0 million . As of December 31, 2019 , there were no outstanding borrowings under the unsecured revolving credit agreement, and the carrying value of the term loan was $498.5 million , which is net of $1.5 million of unamortized debt issuance costs. We were in compliance with all covenants. As of December 31, 2019 , scheduled maturities of total debt for each of the five succeeding fiscal years is as follows: (in thousands) 2020 (1) $ — 2021 — 2022 25,000 2023 50,000 2024 425,000 Total $ 500,000 (1) We repaid $75.0 million of the unsecured term loan in January 2020 prior to its scheduled maturity date. As such, the payment is reflected as current on our consolidated balance sheet but not in the table above.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Income before income taxes included the following components: Year Ended December 31, (in thousands) 2019 2018 2017 Domestic $ 448,271 $ 455,478 $ 344,447 Foreign 74,312 31,607 51,247 Total $ 522,583 $ 487,085 $ 395,694 The provision for income taxes was composed of the following: Year Ended December 31, (in thousands) 2019 2018 2017 Current: Federal $ 44,824 $ 58,138 $ 112,414 State 9,554 12,888 7,879 Foreign 31,421 30,359 18,843 Deferred: Federal (8,833 ) (20,764 ) (7,387 ) State (965 ) (2,901 ) (584 ) Foreign (4,713 ) (10,010 ) 5,278 Total $ 71,288 $ 67,710 $ 136,443 The reconciliation of the U.S. federal statutory tax rate to the consolidated effective tax rate was as follows: Year Ended December 31, 2019 2018 2017 Federal statutory tax rate 21.0 % 21.0 % 35.0 % State income taxes, net of federal benefit 1.5 1.5 1.1 Foreign rate differential 0.8 0.8 0.1 Uncertain tax positions (0.2 ) 0.5 0.3 U.S. tax reform enactment (0.4 ) 0.2 4.5 Valuation allowance release (1.3 ) — — Domestic production activity benefit — — (2.6 ) Benefit from entity structuring activities — (1.4 ) — Research and development credits (2.2 ) (2.3 ) (1.4 ) Stock-based compensation (3.1 ) (3.3 ) (3.1 ) Foreign-derived intangible income deduction (3.8 ) (3.9 ) — Other 1.3 0.8 0.6 13.6 % 13.9 % 34.5 % On December 22, 2017, the U.S. government enacted comprehensive tax legislation commonly referred to as the Tax Cuts and Jobs Act (Tax Reform). Tax Reform made broad and complex changes to the U.S. tax code, including, but not limited to, (1) reducing the U.S. federal corporate tax rate from 35 percent to 21 percent ; (2) requiring companies to pay a one-time federal income tax on certain unrepatriated earnings of foreign subsidiaries (transition tax); (3) generally eliminating U.S. federal income taxes on dividends from foreign subsidiaries; (4) creating a new provision designed to tax global intangible low-taxed income (GILTI) which allows for the possibility of using foreign tax credits (FTCs) and a deduction of up to 50 percent to offset the income tax liability (subject to some limitations); (5) repealing the domestic production activity deduction; (6) creating the foreign-derived intangible income deduction; (7) creating the base erosion anti-abuse tax, a new minimum tax; (8) allowing for full expensing of qualified property through bonus depreciation; and (9) creating limitations on the deductibility of certain executive compensation. The SEC staff issued Staff Accounting Bulletin (SAB) 118, which provides guidance on accounting for the tax effects of Tax Reform. SAB 118 provided a measurement period that was limited to one year from enactment for companies to complete the accounting under ASC 740, Income Taxes . In accordance with SAB 118, throughout the measurement period, a company must reflect the income tax effects of those aspects of Tax Reform for which the accounting under ASC 740 was complete in the financial statements. To the extent that a company’s accounting for certain income tax effects of Tax Reform was incomplete, but a reasonable estimate was able to be made, the company must record a provisional estimate in the financial statements. If a company could not determine a provisional estimate to be included in the financial statements, it should continue to apply ASC 740 on the basis of the tax laws that were in effect immediately before the enactment of Tax Reform. As further discussed below, we finalized our provisional Tax Reform calculations as of the end of the measurement period, based on guidance and information available as of the reporting date. The U.S. government has not yet issued final guidance related to a portion of the new rules enacted as part of Tax Reform. Subsequent adjustments, if any, will be recorded in the period in which guidance is finalized. Our accounting for the impact of the reduction in the U.S. federal corporate tax rate on our deferred tax assets and liabilities is complete. Tax Reform reduced the corporate tax rate to 21 percent , effective January 1, 2018. Consequently, we recorded a net adjustment to deferred income tax expense of $1.9 million for the year ended December 31, 2017 to revalue our deferred tax assets and liabilities. No further adjustments were recorded for the years ended December 31, 2019 and 2018. Our accounting for the transition tax is complete. Reasonable estimates of certain effects were calculated and a provisional adjustment of $16.0 million was recorded in the December 31, 2017 financial statements. To determine the amount of the transition tax, we determined, in addition to other factors, the amount of post-1986 earnings and profits (E&P) of the relevant subsidiaries, as well as the amount of non-U.S. income taxes paid on such earnings. Based on revised E&P calculations updated during the measurement period, we recognized an additional measurement-period adjustment for the year ended December 31, 2018 of $0.9 million to the transition tax obligation and a corresponding adjustment to tax expense. In February 2019, the U.S. government published final regulations relating to transition tax. In accordance with the final regulations, we recognized a post-measurement period reduction for the year ended December 31, 2019 of $1.8 million to the transition tax obligation and a corresponding adjustment to tax expense, resulting in a final transition tax obligation of $15.1 million . We have elected to pay this liability over eight years; however, in accordance with IRS issued guidance, tax overpayments from the year ended December 31, 2017 are required to be applied to the transition tax obligation. Based on this guidance, the entire balance of the obligation has been paid as of December 31, 2019. Our accounting for the indefinite reinvestment assertion is complete. In general, it is our intention to permanently reinvest all earnings in excess of previously taxed amounts. As part of Tax Reform, substantially all of the previous earnings of our non-U.S. subsidiaries were taxed through the transition tax and current earnings are taxed as part of GILTI tax expense. These taxes increased our previously taxed earnings and allow for the repatriation of the majority of our foreign earnings without any residual U.S. federal tax. While we believe that the financial reporting bases may be greater than the tax bases of investments in foreign subsidiaries for any earnings in excess of previously taxed amounts, such amounts are considered permanently reinvested. The cumulative temporary difference related to such permanently reinvested earnings is approximately $32.8 million and we would anticipate the tax effect on those earnings to be immaterial as a result of Tax Reform. During the year ended December 31, 2018, we repatriated $144.3 million of foreign cash. We did not make any adjustments related to our indefinite reinvestment assertion during the years ended December 31, 2019 and 2018. Our accounting policy choice for GILTI is complete. Under U.S. GAAP, we are allowed to make an accounting policy choice of either (1) treating taxes due on future U.S. inclusions in taxable income related to GILTI as a current-period expense when incurred (the period cost method) or (2) factoring such amounts into the measurement of our deferred taxes (the deferred method). We selected the period cost method and recorded GILTI tax expense of $0.6 million and $0.4 million in the financial statements for the years ended December 31, 2019 and 2018, respectively. The components of deferred tax assets and liabilities are as follows: December 31, (in thousands) 2019 2018 Deferred tax assets: Net operating loss carryforwards $ 35,044 $ 39,290 Operating lease liabilities 26,628 — Stock-based compensation 24,254 20,464 Uncertain tax positions 19,227 17,823 Employee benefits 9,392 15,048 Research and development credits 5,865 5,951 Other 6,309 4,121 Valuation allowance (17,524 ) (21,676 ) Total deferred tax assets 109,195 81,021 Deferred tax liabilities: Other intangible assets (99,193 ) (38,787 ) Operating lease right-of-use assets (25,648 ) — Accounting method change (21,396 ) (31,626 ) Deferred revenue (13,744 ) (12,021 ) Property and equipment (3,780 ) (2,034 ) Total deferred tax liabilities (163,761 ) (84,468 ) Net deferred tax liabilities $ (54,566 ) $ (3,447 ) The valuation allowance decreased by $4.2 million for the year ended December 31, 2019. Due to an enacted law change in a foreign jurisdiction during the year ended December 31, 2019, certain expenses will become nondeductible for tax purposes in 2020, resulting in the ability to utilize net operating losses in a jurisdiction where we previously determined utilization was remote. Considering all positive and negative evidence, we determined significant positive evidence exists to release $6.7 million of valuation allowance previously established. This decrease in the valuation allowance is offset by other increases in unrealizable tax assets. 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, 2019 , we had federal net operating loss carryforwards of $4.2 million . These losses expire between 2025 - 2037, and are subject to limitations on their utilization. Deferred tax assets of $0.3 million have been recorded for state operating loss carryforwards. These losses expire between 2030 - 2038, and are subject to limitations on their utilization. We had total foreign net operating loss carryforwards of $142.0 million , of which $113.2 million are not currently subject to expiration dates. The remainder, $28.8 million , expires between 2024 - 2036. We had tax credit carryforwards of $4.1 million , of which $1.2 million are subject to limitations on their utilization. Approximately $0.6 million of these tax credit carryforwards are not currently subject to expiration dates. The remainder, $3.5 million , expires in various years between 2020 - 2039. The following is a reconciliation of the total amounts of unrecognized tax benefits: Year Ended December 31, (in thousands) 2019 2018 2017 Unrecognized tax benefit as of January 1 $ 22,827 $ 19,657 $ 15,209 Gross increases—acquisitions 26,914 — — Gross increases—tax positions in prior period 207 1,229 905 Gross decreases—tax positions in prior period (1,743 ) (376 ) (765 ) Gross increases—tax positions in current period 3,563 4,014 3,757 Reductions due to a lapse of the applicable statute of limitations (2,230 ) (994 ) (847 ) Changes due to currency fluctuation (453 ) (703 ) 1,414 Settlements — — (16 ) Unrecognized tax benefit as of December 31 $ 49,085 $ 22,827 $ 19,657 We believe that it is reasonably possible that approximately $8.3 million of uncertain tax positions included in the table above 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. If the unrecognized tax benefit as of December 31, 2019 were to be recognized, a benefit of $47.3 million would impact the effective tax rate. We recognize interest and penalties related to income taxes as income tax expense. During the years ended December 31, 2019 , 2018 and 2017, we recorded penalty expense of $0.5 million , $0.8 million and $1.1 million , respectively. We recorded interest expense of less than $0.1 million , interest income of $0.1 million and interest expense of $0.4 million for the years ended December 31, 2019, 2018 and 2017, respectively. As of December 31, 2019 , we accrued a liability for penalties of $11.7 million and interest of $6.6 million . As of December 31, 2018 , we accrued a liability for penalties of $4.7 million and interest of $4.0 million . We are subject to taxation in the U.S. and various states and foreign jurisdictions. In the U.S., our only major tax jurisdiction, the 2016 - 2019 tax years are open to examination by the Internal Revenue Service.

Pension And Profit-Sharing Plan

Pension And Profit-Sharing Plans	12 Months Ended
	Dec. 31, 2019
Retirement Benefits [Abstract]
Pension And Profit-Sharing Plans	Pension and Profit-Sharing Plans We have a 401(k)/profit-sharing plan for all qualifying domestic employees that permits participants to defer a portion of their pay pursuant to Section 401(k) of the Internal Revenue Code. We make 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. We 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 . We also maintain and contribute to various defined contribution and defined benefit pension arrangements for our international employees. We meet the minimum statutory funding requirements for our foreign plans. As of December 31, 2019 , the total unfunded portion of the defined benefit obligations is $11.2 million . Expenses related to our retirement programs were $16.3 million in 2019 , $12.4 million in 2018 and $10.1 million in 2017 .

Non-Compete and Employment Agre

Non-Compete and Employment Agreements	12 Months Ended
	Dec. 31, 2019
Non-Compete and Employment Agreements [Abstract]
Non-Compete and Employment Agreements	Non-Compete and Employment Agreements Our employees 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 us anywhere in the world while employed by us (and, in some cases, for specified periods thereafter in relevant geographic areas), and that any products or technology created by them during their term of employment are our property. In addition, we require all channel partners to enter into agreements not to disclose our trade secrets and other proprietary information. We have an employment agreement with our Chief Executive Officer. This agreement provides for, among other things, in the case of termination by us other than for Cause (as defined therein) or by the Chief Executive Officer for Good Reason (as defined therein) and subject to his execution and delivery of a release of claims against us, he will receive minimum severance payments equal to the sum of two times his base salary and target bonus to be paid out over two years from the date of termination and up to two years of COBRA payments for health care coverage after termination. During his employment with us and for two years thereafter, following termination of employment under certain circumstances described in the contract, he will be subject to non-competition and non-solicitation obligations. We also have employment agreements with several other employees, primarily in foreign jurisdictions. The terms of these employment agreements generally include annual compensation and non-compete clauses.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2019
Share-based Payment Arrangement [Abstract]
Stock-Based Compensation	Stock-Based Compensation We have an equity incentive plan - the Fifth Amended and Restated ANSYS, Inc. 1996 Stock Option and Grant Plan (Stock Plan). The Stock Plan, as amended, authorizes the grant of approximately 39.8 million shares of our 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 any stock option 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 that are 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. Shares associated with unexercised options or reacquired shares of common stock (except those shares withheld as a result of tax withholding, shares used to pay an option exercise price or pursuant to a net issuance) become available again for option grants and common stock-related awards under the Stock Plan. The Compensation Committee of the Board of Directors may, at its sole discretion, accelerate the date or dates on which an award granted under the Stock Plan may vest or extend, in the case of a stock option, the exercise period up to the expiration date of the option, subject to the terms and conditions of the Stock Plan. Upon termination of service of a participant due to the participant’s death or disability, the vesting of restricted stock units held by the participant accelerates (in case of performance-based vesting, subject to the attainment of the performance requirement). 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 on or 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 at the discretion of the Compensation Committee and 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. We currently issue shares related to exercised stock options or vested awards from our existing pool of treasury shares and have no specific policy to repurchase treasury shares as stock options are exercised or as awards vest. If the treasury pool is depleted, we will issue new shares. Total stock-based compensation expense recognized for the years ended December 31, 2019 , 2018 and 2017 is as follows: Year Ended December 31, (in thousands, except per share amounts) 2019 2018 2017 Cost of sales: Software licenses $ — $ — $ 969 Maintenance and service 8,494 5,224 2,533 Operating expenses: Selling, general and administrative 60,639 47,099 30,817 Research and development 47,057 31,023 18,835 Stock-based compensation expense before taxes 116,190 83,346 53,154 Related income tax benefits (47,454 ) (34,518 ) (20,503 ) Stock-based compensation expense, net of taxes $ 68,736 $ 48,828 $ 32,651 Net impact on earnings per share: Basic earnings per share $ (0.82 ) $ (0.58 ) $ (0.38 ) Diluted earnings per share $ (0.80 ) $ (0.57 ) $ (0.38 ) Stock Options Prior to 2017, we granted stock option awards. The value of each stock option award was estimated on the date of grant, or date of acquisition for options issued in a business combination, using the Black-Scholes option pricing model (Black-Scholes model). The determination of the fair value of stock-based payment awards using an option pricing model was affected by our stock price as well as assumptions regarding a number of complex and subjective variables. These variables included our stock volatility during the preceding six years, actual and projected employee stock option exercise behaviors, interest rate assumptions using the five-year U.S. Treasury Note yield on date of grant or acquisition date, and expected dividends. The stock-based compensation expense for options is recorded ratably over the requisite service period. Forfeitures of awards are accounted for as they occur. As of December 31, 2019 , total unrecognized estimated compensation cost related to unvested stock options granted prior to that date was $1.0 million , which is expected to be recognized over a weighted average period of less than 1.0 year . Information regarding stock option transactions is summarized below: Year Ended December 31, 2019 2018 2017 (options in thousands) Options Weighted- Average Exercise Price Options Weighted- Average Exercise Price Options Weighted- Average Exercise Price Outstanding, beginning of year 1,484 $ 62.80 2,170 $ 59.17 3,136 $ 56.37 Granted — $ — — $ — — $ — Exercised (495 ) $ 53.53 (679 ) $ 50.92 (956 ) $ 49.78 Forfeited (5 ) $ 64.21 (7 ) $ 86.28 (10 ) $ 80.92 Outstanding, end of year 984 $ 67.49 1,484 $ 62.80 2,170 $ 59.17 Vested and Exercisable, end of year 924 $ 65.71 1,347 $ 59.69 1,930 $ 55.11 Nonvested 60 $ 94.77 137 $ 93.44 240 $ 91.71 2019 2018 2017 Weighted Average Remaining Contractual Term (in years) Outstanding 3.18 3.55 4.10 Vested and Exercisable 2.95 3.14 3.57 Nonvested 6.71 7.60 8.30 Aggregate Intrinsic Value (in thousands) Exercised $ 72,098 $ 78,648 $ 58,472 Outstanding $ 186,926 $ 118,908 $ 191,895 Vested and Exercisable $ 177,111 $ 112,133 $ 178,456 Nonvested $ 9,815 $ 6,775 $ 13,439 Compensation Expense - Stock Options (in thousands) $ 1,709 $ 2,006 $ 2,948 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. Information regarding stock options outstanding as of December 31, 2019 is summarized below: (options in thousands) Options Outstanding Options Exercisable Options Unvested Range of Exercise Prices Options Weighted- Weighted- Options Weighted- Average Remaining Contractual Life (years) Weighted- Options Weighted- Average Remaining Contractual Life (years) Weighted- Average Exercise Price $11.99 - $48.97 181 1.01 $ 43.29 181 1.01 $ 43.29 — 0.00 $ — $58.67 267 1.87 $ 58.67 267 1.87 $ 58.67 — 0.00 $ — $67.44 280 2.87 $ 67.44 280 2.87 $ 67.44 — 0.00 $ — $76.31 - $95.09 256 6.44 $ 93.89 196 6.36 $ 93.62 60 6.71 $ 94.77 Restricted Stock Units Under the terms of the Fifth Amended and Restated ANSYS, Inc. 1996 Stock Option and Grant Plan, we issue various restricted stock unit awards. The following table summarizes the types of awards and vesting conditions: Award Vesting Period Vesting Condition Restricted stock units with a market and service condition Three years Our performance measured by total stockholder return relative to the Nasdaq Composite Index for the measurement period and subject to continued employment through the vesting period. Restricted stock units with an operating performance and service condition Three years Operating performance metrics as defined at the beginning of the performance cycle. Restricted stock units with a service condition only Three or four years Continued employment through the yearly vesting period. The fair values of restricted stock units (RSUs) with a market condition were estimated using a Monte Carlo simulation model and are recognized over the vesting period. The determination of the fair values of the awards was affected by the grant date and several variables, each of which has been identified in the chart below: Year Ended December 31, Assumptions used in Monte Carlo lattice pricing model 2019 2018 2017 Risk-free interest rate 2.5% 2.4% 1.5% Expected dividend yield —% —% —% Expected volatility—Ansys stock price 23% 21% 19% Expected volatility—Nasdaq Composite Index 16% 15% 15% Expected term 2.8 years 2.8 years 2.8 years Correlation factor 0.71 0.65 0.70 Weighted average fair value per share $238.99 $191.76 $120.94 The fair value of RSUs with operating performance metrics is based on the fair market value of our stock on the date of the grant and is recognized from the grant date through the conclusion of the measurement period associated with each operating performance metric based on management's estimates concerning the probability of vesting. The fair value of RSUs with only a service condition is based on the fair market value of our stock on the date of the grant and is recognized over the vesting period. Total compensation expense for employee RSU awards recorded for the years ended December 31, 2019 , 2018 and 2017 was $109.9 million , $77.4 million and $46.3 million , respectively. Information regarding all employee RSU transactions is summarized below: Year Ended December 31, 2019 2018 2017 (RSUs in thousands) RSUs Weighted- Average Grant Date Fair Value RSUs Weighted- Average Grant Date Fair Value RSUs Weighted- Average Grant Date Fair Value Nonvested, beginning of year 1,522 $ 129.96 1,361 $ 100.66 906 $ 86.45 Granted (1) 843 $ 192.37 681 $ 163.67 866 $ 109.67 Performance adjustment (2) 74 $ 167.87 76 $ 151.52 35 $ 98.29 Vested (704 ) $ 125.84 (524 ) $ 101.38 (341 ) $ 88.58 Forfeited (117 ) $ 140.43 (72 ) $ 125.29 (105 ) $ 90.80 Nonvested, end of year 1,618 $ 165.26 1,522 $ 129.96 1,361 $ 100.66 (1) Includes all RSUs granted during the year. RSUs with operating performance conditions are issued annually and have one or three performance cycles. Performance conditions are assigned at the beginning of each performance cycle and are reflected as grants at target at that time. (2) RSUs with a market or performance condition are granted at target and vest based on achievement of the market or operating performance and service conditions. The actual number of RSUs issued may be more or less than the target RSUs depending on the achievement of the market or operating performance conditions. Board of Directors During and prior to 2015, we granted deferred stock awards to non-employee Directors, which are rights to receive shares of common stock upon termination of service as a Director. Associated with these awards, we 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 Ansys shares into a variety of non-Ansys-stock investment options in order to diversify a portion of their holdings, subject to meeting ownership guidelines. Information regarding deferred stock awards to non-employee Directors is summarized below: Year Ended December 31, 2019 Diversified Undiversified Total Deferred Awards Outstanding, beginning of year 12,250 120,449 132,699 Shares Diversified 13,348 (13,348 ) — Shares Issued Upon Retirement (20,000 ) (47,020 ) (67,020 ) Deferred Awards Outstanding, end of year 5,598 60,081 65,679 In 2019 , 2018 and 2017 , we granted 11,259 , 13,632 and 18,018 RSUs to non-employee Directors, respectively, which will vest in full upon the earlier of one year from the date of grant or the date of the next regular meeting of stockholders. If a non-employee Director retires prior to the vest date, the non-employee Director receives a pro-rata portion of the RSUs. The weighted-average grant date fair values per RSU were $187.53 , $165.71 and $123.38 for the years ended December 31, 2019 , 2018 and 2017 , respectively. Total compensation expense associated with the awards recorded for the years ended December 31, 2019 , 2018 and 2017 was $2.5 million, $2.3 million and $2.6 million, respectively. Employee Stock Purchase Plan Our 1996 Employee Stock Purchase Plan (the “Purchase Plan”) was adopted by the Board of Directors on April 19, 1996 and was subsequently approved by our 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 our stock 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 in which the option is outstanding at any time. As of December 31, 2019 , 1.6 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, 2019 , 2018 and 2017 was $2.0 million , $1.8 million and $1.2 million , respectively.

Stock Repurchase Program

Stock Repurchase Program	12 Months Ended
	Dec. 31, 2019
Class of Stock Disclosures [Abstract]
Stock Repurchase Program	Stock Repurchase Program Under our stock repurchase program, we repurchased shares as follows: Year Ended December 31, (in thousands, except per share data) 2019 2018 2017 Number of shares repurchased 330 1,674 2,750 Average price paid per share $ 179.41 $ 161.12 $ 122.20 Total cost $ 59,116 $ 269,801 $ 336,042 In February 2018, our 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, 2019 , 3.5 million shares remained available for repurchase under the program.

Royalty Agreements

Royalty Agreements	12 Months Ended
	Dec. 31, 2019
Royalty Agreements [Abstract]
Royalty Agreements	Royalty Agreements We have entered into various renewable license agreements under which we have been granted access to the licensor's technology and the right to sell the technology in our 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 software licenses and were $22.4 million , $16.9 million and $16.0 million for the years ended December 31, 2019 , 2018 and 2017 , respectively.

Geographic Information

Geographic Information	12 Months Ended
	Dec. 31, 2019
Segments, Geographical Areas [Abstract]
Geographic Information	Geographic Information Revenue to external customers is attributed to individual countries based upon the location of the customer. Revenue by geographic area was as follows: Year Ended December 31, (in thousands) 2019 2018 2017 United States $ 637,916 $ 506,335 $ 417,343 Japan 162,154 145,951 126,097 Germany 158,809 140,506 108,211 South Korea 90,082 72,724 63,011 France 68,551 67,657 53,672 China 64,725 57,567 54,415 Other EMEA 211,193 193,317 166,472 Other international 122,462 109,579 106,029 Total revenue $ 1,515,892 $ 1,293,636 $ 1,095,250 Property and equipment by geographic area was as follows: December 31, (in thousands) 2019 2018 United States $ 59,473 $ 46,605 India 5,660 4,176 Germany 4,237 2,158 United Kingdom 4,194 1,238 Other EMEA 5,532 3,724 Other international 4,540 3,754 Total property and equipment, net $ 83,636 $ 61,655

Unconditional Purchase Obligati

Unconditional Purchase Obligations	12 Months Ended
	Dec. 31, 2019
Unconditional Purchase Obligations (Excluding Capital Stock Redemptions) [Abstract]
Unconditional Purchase Obligations	Unconditional Purchase Obligations We have entered into various unconditional purchase obligations which primarily include royalties and software licenses and services . We expended $24.2 million , $22.4 million and $14.1 million related to unconditional purchase obligations that existed as of the beginning of each year for the years ended December 31, 2019 , 2018 and 2017 , respectively. Future expenditures under unconditional purchase obligations in effect as of December 31, 2019 are as follows: (in thousands) 2020 $ 37,183 2021 14,034 2022 10,689 2023 6,212 2024 3,264 Total $ 71,382

Restructuring

Restructuring	12 Months Ended
	Dec. 31, 2019
Restructuring and Related Activities [Abstract]
Restructuring	Restructuring During the fourth quarter of 2016, we initiated workforce realignment activities to reallocate resources to align with our future strategic plans. We completed the workforce realignment activities as of September 30, 2017. We incurred related restructuring charges as follows: (in thousands) Gross Net of Tax Q4 2016 $ 3,419 $ 2,355 Q1 2017 9,273 6,176 Q2 2017 2,000 1,435 Q3 2017 466 331 Total restructuring charges $ 15,158 $ 10,297 The restructuring charges are included in the presentation of cost of software licenses; cost of maintenance and service; research and development expense; and selling, general and administrative expense. The gross charges were fully paid as of March 31, 2018.

Contingencies and Commitments

Contingencies and Commitments	12 Months Ended
	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Contingencies and Commitments	Contingencies and Commitments We are 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 our opinion, the resolution of pending matters is not expected to have a material adverse effect on our 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 our results of operations, cash flows or financial position. Our Indian subsidiary has several service tax audits pending that have resulted in formal inquiries being received on transactions through mid-2012. We could incur tax charges and related liabilities of approximately $7.2 million . The service tax issues raised in our notices and inquiries are very similar to the case, M/s Microsoft Corporation (I) (P) Ltd. Vs. Commissioner of Service Tax, New Delhi, wherein the Delhi Customs, Excise and Service Tax Appellate Tribunal (CESTAT) passed a favorable ruling to Microsoft. The Microsoft case ruling was subsequently challenged in the Supreme Court by the Indian tax authority. We can provide no assurances on the impact that the present Microsoft case’s decision will have on our cases. We are uncertain as to when these service tax matters will be concluded. We sell software licenses and services to our customers under contractual agreements. Such agreements generally include certain provisions indemnifying the customer against claims of intellectual property infringement by third parties arising from such customer’s usage of our products or services. To date, payments related to these indemnification provisions have been immaterial. For several reasons, including the lack of prior material indemnification claims, we cannot determine the maximum amount of potential future payments, if any, related to such indemnification provisions.

Schedule II - Valuation and Qua

Schedule II - Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2019
SEC Schedule, 12-09, 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, 2019 $ 8,000 $ 2,928 $ 2,228 $ 8,700 Year ended December 31, 2018 $ 6,800 $ 1,577 $ 377 $ 8,000 Year ended December 31, 2017 $ 5,700 $ 1,474 $ 374 $ 6,800

Summary Of Significant Accounti

Summary Of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Accounting Principles	Accounting Principles The financial statements and accompanying notes are prepared in accordance with accounting principles generally accepted in the United States. Certain items in the consolidated financial statements and the notes to the consolidated financial statements of prior years have been reclassified to conform to the current year's presentation. These reclassifications had no effect on reported net income, comprehensive income, cash flows, total assets or total liabilities and stockholders' equity.
Principles Of Consolidation	Principles of Consolidation The accompanying consolidated financial statements include our accounts and those of our wholly owned subsidiaries. All intercompany accounts and transactions have been eliminated.
Recently Adopted Accounting Guidance	Recently Adopted Accounting Guidance Leases: In February 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2016-02, Leases (Topic 842) (ASU 2016-02). We adopted ASU 2016-02 and its related amendments (collectively known as Accounting Standards Codification (ASC) 842) on January 1, 2019 using the modified retrospective approach. Results for reporting periods beginning after January 1, 2019 are presented under ASC 842, while prior period amounts are not adjusted and continue to be reported in accordance with ASC 840, Leases . ASC 842 requires virtually all leases, other than leases of intangible assets, to be recorded on the balance sheet with a right-of-use (ROU) asset and a corresponding lease liability. We elected the package of practical expedients permitted under the transition guidance within the new standard, which allowed us to carry forward our historical assessments of whether a contract contains a lease, lease classification and initial direct costs. In addition, we elected the accounting policy to combine the lease and nonlease components as a single component for all asset classes. We determine if an arrangement is a lease at inception. Leases are classified as either operating or finance leases based on certain criteria. This classification determines the timing and presentation of expenses on the income statement, as well as the presentation of the related cash flows and balance sheet. Operating leases are recorded on the balance sheet as operating lease right-of-use assets, other accrued expenses and liabilities, and long-term operating lease liabilities. We currently have no finance leases. ROU assets and related liabilities are recorded at lease commencement based on the present value of the lease payments over the expected lease term. Lease payments include future increases unless the increases are based on changes in an index or rate. As our leases do not usually provide an implicit rate, our incremental borrowing rate is used to calculate ROU assets and related liabilities. The incremental borrowing rate is determined based on our estimated credit rating, the term of the lease, the economic environment where the asset resides and full collateralization. The ROU assets and related lease liabilities include optional renewals for which we are reasonably certain to exercise; whereas, optional terminations are included unless it is reasonably certain not to be elected. The adoption of the new standard resulted in the recognition of ROU assets of $90.9 million and lease liabilities of $92.5 million , and corresponding deferred tax assets and liabilities, on our consolidated balance sheet as of January 1, 2019. The adoption had no impact on our consolidated statements of income or cash flows. Implementation cost accounting for cloud computing arrangements: In August 2018, the FASB issued ASU No. 2018-15, Intangibles—Goodwill and Other—Internal-Use Software (Subtopic 350-40): Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract (ASU 2018-15). The standard aligns the accounting for costs incurred to implement a cloud computing arrangement (CCA) that is a service arrangement with the guidance on capitalizing costs associated with developing or obtaining internal-use software. Under ASU 2018-15, an entity would apply Subtopic 350-40 to determine which implementation costs related to a CCA that is a service contract should be capitalized. The standard does not change the accounting for the service component of a CCA. The associated cash flows will be reflected within operating activities. We retrospectively adopted the guidance during the quarter ended December 31, 2019. The adoption resulted in the reclassification of cash flows associated with implementation costs related to CCAs that are service contracts on our consolidated statements of cash flows. This resulted in a decrease to operating cash flows, and a corresponding increase to investing cash flows, of $2.5 million , $1.4 million and $2.8 million for the years ending December 31, 2019, 2018 and 2017, respectively. The adoption had no impact on our consolidated balance sheets or consolidated statements of income.
Accounting Guidance Issued And Not Yet Adopted	Accounting Guidance Issued and Not Yet Adopted Credit losses: In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (ASU 2016-13). The current guidance requires the allowance for doubtful accounts to be estimated based on an incurred loss model, which considers past and current conditions. ASU 2016-13 requires companies to use an expected loss model that also considers reasonable and supportable forecasts of future conditions. ASU 2016-13 is effective for annual periods beginning after December 15, 2019, including interim periods within that reporting period. Early adoption is permitted for annual periods beginning after December 15, 2018, including interim periods within that reporting period. The standard requires a cumulative-effect adjustment to the balance sheet as of the beginning of the first reporting period in which the guidance is effective. We will adopt the standard effective January 1, 2020 and do not expect the adoption of the new standard to have a material effect on our consolidated financial statements. Income taxes: In December 2019, the FASB issued ASU No. 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes (ASU 2019-12), as part of its initiative to reduce complexity in the accounting standards. The amendments in ASU 2019-12 eliminate certain exceptions related to the approach for intraperiod tax allocation, the methodology for calculating income taxes in an interim period and the recognition of deferred tax liabilities for outside basis differences. ASU 2019-12 also clarifies and simplifies other aspects of the accounting for income taxes. ASU 2019-12 is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020. Early adoption is permitted, including adoption in any interim period. We are currently evaluating the impact that this guidance will have upon our financial position and results of operations, if any.
Use Of Estimates	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, including those related to the Tax Cuts and Jobs Act • Uncertain tax positions • Tax valuation reserves • Fair value of stock-based compensation and probabilities of performance award attainment • Contract revenue • Standalone selling prices of our products and services • Acquired deferred revenue • Useful lives for depreciation and amortization • Valuations of goodwill and other intangible assets • Deferred compensation • Loss contingencies • Operating lease assets and liabilities 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 Recognition Our revenue is derived principally from the licensing of computer software products and from related maintenance contracts. We adopted ASC 606 on January 1, 2018. ASC 606 requires an entity to evaluate revenue recognition by identifying a contract with a customer, identifying the performance obligations in the contract, determining the transaction price, allocating the transaction price to the performance obligations in the contract, and recognizing revenue when (or as) the entity satisfies a performance obligation. Revenue Recognition Policy 2019 and 2018 (ASC 606) We enter into contracts that include combinations of products, maintenance and services, which are accounted for as separate performance obligations with differing revenue recognition patterns. Revenue from perpetual licenses is classified as software license revenue. Software license revenue is recognized up front upon delivery of the licensed product and/or the utility that enables the customer to access authorization keys, provided that an enforceable contract has been received. Typically, our perpetual licenses are sold with post-contract support (PCS), which includes unspecified technical enhancements and customer support. We allocate value in bundled perpetual and PCS arrangements based on the standalone selling prices of the perpetual license and PCS. Revenue from PCS is classified as maintenance revenue and is recognized ratably over the term of the contract, as we satisfy the PCS performance obligation over time. In addition to perpetual licenses, we sell time-based lease licenses. Lease licenses are sold only as a bundled arrangement that includes the rights to a term software license and PCS. Utilizing observable inputs, we determined that 50% of the estimated standalone selling price of the lease license is attributable to the term license and 50% is attributable to the PCS. This determination considered the value relationship for our products between PCS to time-based lease licenses, the value relationship between PCS and perpetual licenses, the average economic life of our products, software renewal rates and the price of the bundled arrangement in relation to the perpetual licensing approach. Consistent with the perpetual sales, the license component is classified as software license revenue and recognized as revenue up front at the commencement of the lease upon delivery of the licensed product and/or utility that enables the customer to access authorization keys. The PCS is classified as maintenance revenue and is recognized ratably over the term of the contract, as we satisfy the PCS performance obligation over time. Revenue from training, support and other services is recognized as the services are performed. For contracts in which the service consists of a single performance obligation, such as providing a training class to a customer, we recognize revenue upon completion of the performance obligation. For service contracts that are longer in duration and often include multiple performance obligations (for example, both training and consulting), we measure the progress toward completion of the obligations and recognize revenue accordingly. In measuring progress towards the completion of performance obligations, we typically utilize output-based estimates for services with contractual billing arrangements that are not based on time and materials, and estimate 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. Proceeds from customers for the purpose of expediting road-map items, developing new products or creating specific features and functionality for existing products is classified as revenue. We also execute arrangements through independent channel partners in which the channel partners are authorized to market and distribute our software products to end users of our 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. We recognize revenue from transactions with channel partners in a manner consistent with the direct sales described above for both perpetual and time-based licenses. Revenue from channel partner transactions is the amount remitted to us by the channel partners. This amount includes a fee for PCS that is compensation for providing technical enhancements and the second level of technical support to the end user, which is recognized over the period that PCS is to be provided. 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. We do not offer right of return. We warrant to our customers that our software will perform substantially as specified in our current user manuals. We have not experienced significant claims related to software warranties beyond the scope of maintenance support, which we are already obligated to provide. The warranty is not sold, and cannot be purchased, separately. The warranty does not provide any type of additional service to the customer or performance obligation for us. Our agreements with our customers generally require us to indemnify the customer against claims that our software infringes third-party patent, copyright, trademark or other proprietary rights. Such indemnification obligations are generally limited in a variety of industry-standard respects, including our right to replace an infringing product. Significant Judgments (ASC 606) Our contracts with customers typically include promises to transfer licenses and services to a customer. Judgment is required to determine if the promises are separate performance obligations, and if so, to allocate the transaction price to each performance obligation. We use the estimated standalone selling price method to allocate the transaction price for each performance obligation. The estimated standalone selling price is determined using all information reasonably available to us, including market conditions and other observable inputs. The corresponding revenues are recognized as the related performance obligations are satisfied. We apply a practical expedient to expense sales commissions as incurred when the amortization period would have been one year or less. Sales commissions associated with the initial year of multi-year contracts are expensed as incurred due to their immateriality. Sales commissions associated with multi-year contracts beyond the initial year are subject to an employee service requirement and are expensed as incurred as they are not considered incremental costs to obtain a contract. We are required to adjust promised amounts of consideration for the effects of the time value of money if the timing of the payments provides the customer or us with a significant financing benefit. We consider various factors in assessing whether a financing component exists, including the duration of the contract, market interest rates and the timing of payments. Our contracts do not include a significant financing component requiring adjustment to the transaction price. Revenue Recognition Policy 2017 (ASC 605) Revenue from perpetual licenses was classified as license revenue and was recognized upon delivery of the licensed product and/or the utility that enabled the customer to access authorization keys, provided that acceptance had occurred and a signed contractual obligation was received, the price was fixed and determinable, and collectibility of the receivable was probable. We determined the fair value of PCS sold together with perpetual licenses based on the rate charged for PCS when sold separately. Revenue from PCS contracts was classified as maintenance and service revenue and was recognized ratably over the term of the contract. Revenue for software lease licenses was classified as license revenue and was recognized over the period of the lease contract. Typically, our software leases include PCS which, due to the short term (principally one year or less) of our software lease licenses, were not permitted to be separated from lease revenue for accounting purposes. As a result, both the lease licenses and PCS were recognized ratably over the lease period. We included the revenue for the entire lease arrangement within software license revenue in the consolidated statements of income. Many of our semiconductor products are typically licensed via longer term leases of 24 – 36 months. We recognized revenue for these licenses over the term of the lease contract. Because we did not have vendor-specific objective evidence of the fair value of these leases, we also recognized 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 was recognized as the services were performed. We applied the specific performance method to contracts in which the service consisted of a single act, such as providing a training class to a customer, and the proportional performance method to other service contracts that were longer in duration and often included multiple acts (for example, both training and consulting). In applying the proportional performance method, we typically utilized output-based estimates for services with contractual billing arrangements that were not based on time and materials, and estimated output based on the total tasks completed as compared to the total tasks required for each work contract. Input-based estimates were utilized for services that involved general consultations with contractual billing arrangements based on time and materials, utilizing direct labor as the input measure. The accounting treatment under ASC 605 associated with arrangements through independent channel partners, non-income related taxes, warranties and indemnification obligations is consistent with the accounting treatment under ASC 606 described above.
Cash And Cash Equivalents	Cash and Cash Equivalents Cash and cash equivalents consist primarily of highly liquid investments such as deposits held at major banks and money market funds. Cash equivalents are carried at cost, which approximates fair value. Our cash and cash equivalents balances comprise the following: December 31, 2019 December 31, 2018 (in thousands, except percentages) Amount % of Total Amount % of Total Cash accounts $ 549,639 63.0 $ 331,084 42.6 Money market funds 322,455 37.0 446,055 57.4 Total $ 872,094 $ 777,139 Our money market fund balances are held in various funds of a single issuer.
Property And Equipment	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 year 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 Research and development costs are expensed as incurred. Internally developed software costs required to be capitalized as defined by the accounting guidance are not material to our consolidated financial statements.
Business Combinations	Business Combinations When we consummate 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 acquisition date fair value of the net identifiable assets acquired. 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, our 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, we record adjustments to the assets acquired and liabilities assumed with the corresponding offset to goodwill as we obtain 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 and Other Intangible Assets Goodwill represents the excess of the fair value of 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 range from two years to seventeen years . Amortization expense for intangible assets was $36.9 million , $40.8 million and $49.8 million for the years ended December 31, 2019 , 2018 and 2017 , respectively. We test 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. We have one reporting unit. Goodwill is tested at this reporting unit level and indefinite-lived intangible assets are tested at the individual asset level. This requires us 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. We perform our annual impairment tests for goodwill and indefinite-lived intangible assets as of January 1 of each year unless there is an indicator that would require a test during the year. We periodically review 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	Concentrations of Credit Risk We have 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 our products. We perform periodic credit evaluations of our customers' financial condition and generally do not require collateral. The following table outlines concentrations of risk with respect to our revenue: Year Ended December 31, (as a % of revenue) 2019 2018 2017 Revenue from channel partners 23 % 22 % 25 % Largest channel partner 4 % 4 % 5 % 2 nd largest channel partner 2 % 2 % 2 % No single customer accounted for more than 5% of our revenue in 2019 , 2018 or 2017 . In addition to the concentration of credit risk with respect to trade receivables, our cash and cash equivalents are also exposed to concentration risk. Our cash and cash equivalent accounts are insured through various public and private bank deposit insurance programs, foreign and domestic; however, a significant portion of our funds are not insured. The following table outlines concentrations of risk with respect to our cash and cash equivalents: As of December 31, (in thousands) 2019 2018 Cash and cash equivalents held domestically $ 626,433 $ 616,249 Cash and cash equivalents held by foreign subsidiaries 245,661 160,890 Cash and cash equivalents held in excess of deposit insurance, foreign and domestic 855,721 754,163 Largest balance of cash and cash equivalents held with one financial institution, foreign and domestic 330,551 452,166
Allowance For Doubtful Accounts	Allowance for Doubtful Accounts We make judgments as to our ability to collect outstanding receivables and provide 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, we consider our historical collection experience and current economic trends in the customer's industry and geographic region. We recorded provisions for bad debts of $2.9 million , $1.6 million and $1.5 million for the years ended December 31, 2019, 2018 and 2017, respectively.
Income Taxes	Income Taxes We account 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. We record net deferred tax assets to the extent we believe these assets will more likely than not be realized. In making such determination, we consider 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 we determine that we 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 its examination even though the statute of limitations remains open. We recognize interest and penalties related to income taxes within the income tax expense line in the consolidated statements of income. Accrued interest and penalties are included within the related tax liability line in the consolidated balance sheets.
Foreign Currencies	Foreign Currencies Certain of our 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 our functional currency or our subsidiaries' functional currencies are translated at the effective exchange rate on the balance sheet date. Gains and losses resulting from foreign exchange transactions are included in other expense, net. We recorded net foreign exchange losses of $2.5 million , $3.1 million and $1.9 million for the years ended December 31, 2019 , 2018 and 2017, respectively. The financial statements of our 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 Accumulated other comprehensive loss is composed entirely of foreign currency translation adjustments.
Earnings Per Share	Earnings Per Share Basic earnings per share (EPS) amounts are computed by dividing earnings by the weighted average number of common shares outstanding during the period. Diluted EPS amounts assume the issuance of common stock for all potentially dilutive equivalents outstanding. To the extent stock awards are anti-dilutive, they are excluded from the calculation of diluted EPS. The details of basic and diluted EPS are as follows: Year Ended December 31, (in thousands, except per share data) 2019 2018 2017 Net income $ 451,295 $ 419,375 $ 259,251 Weighted average shares outstanding – basic 84,259 83,973 84,988 Dilutive effect of stock plans 1,666 1,940 1,866 Weighted average shares outstanding – diluted 85,925 85,913 86,854 Basic earnings per share $ 5.36 $ 4.99 $ 3.05 Diluted earnings per share $ 5.25 $ 4.88 $ 2.98 Anti-dilutive shares 14 7 84
Stock-Based Compensation	Stock-Based Compensation We account 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 services in exchange for the award, typically the vesting period.
Fair Value Of Financial Instruments	Fair Value of Financial Instruments We account 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.

Summary Of Significant Accoun_2

Summary Of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2019
Summary Of Cash And Cash Equivalents	Our cash and cash equivalents balances comprise the following: December 31, 2019 December 31, 2018 (in thousands, except percentages) Amount % of Total Amount % of Total Cash accounts $ 549,639 63.0 $ 331,084 42.6 Money market funds 322,455 37.0 446,055 57.4 Total $ 872,094 $ 777,139
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) 2019 2018 2017 Net income $ 451,295 $ 419,375 $ 259,251 Weighted average shares outstanding – basic 84,259 83,973 84,988 Dilutive effect of stock plans 1,666 1,940 1,866 Weighted average shares outstanding – diluted 85,925 85,913 86,854 Basic earnings per share $ 5.36 $ 4.99 $ 3.05 Diluted earnings per share $ 5.25 $ 4.88 $ 2.98 Anti-dilutive shares 14 7 84
Customer Concentration Risk
Schedule Of Risk Concentration	The following table outlines concentrations of risk with respect to our revenue: Year Ended December 31, (as a % of revenue) 2019 2018 2017 Revenue from channel partners 23 % 22 % 25 % Largest channel partner 4 % 4 % 5 % 2 nd largest channel partner 2 % 2 % 2 %
Credit Concentration Risk
Schedule Of Risk Concentration	The following table outlines concentrations of risk with respect to our cash and cash equivalents: As of December 31, (in thousands) 2019 2018 Cash and cash equivalents held domestically $ 626,433 $ 616,249 Cash and cash equivalents held by foreign subsidiaries 245,661 160,890 Cash and cash equivalents held in excess of deposit insurance, foreign and domestic 855,721 754,163 Largest balance of cash and cash equivalents held with one financial institution, foreign and domestic 330,551 452,166

Revenue from Contracts with C_2

Revenue from Contracts with Customers (Tables)	12 Months Ended
	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	The following table summarizes revenue: Year Ended December 31, (in thousands) 2019 2018 2017 Revenue: Lease licenses $ 406,043 $ 275,619 $ 376,886 Perpetual licenses 293,587 301,098 248,078 Software licenses 699,630 576,717 624,964 Maintenance 760,574 676,883 440,428 Service 55,688 40,036 29,858 Maintenance and service 816,262 716,919 470,286 Total revenue $ 1,515,892 $ 1,293,636 $ 1,095,250 Direct revenue, as a percentage of total revenue 77.1 % 77.6 % 75.2 % Indirect revenue, as a percentage of total revenue 22.9 % 22.4 % 24.8 %
Changes in Deferred Revenue	The changes in deferred revenue, inclusive of both current and long-term deferred revenue, during the years ended December 31, 2019 and 2018 were as follows: (in thousands) 2019 2018 Beginning balance – January 1 $ 343,174 $ 299,730 Acquired deferred revenue 6,880 2,470 Deferral of revenue 1,532,549 1,339,964 Recognition of deferred revenue (1,515,892 ) (1,293,636 ) Currency translation (1,437 ) (5,354 ) Ending balance – December 31 $ 365,274 $ 343,174
Remaining Performance Obligations, Expected Timing of Satisfaction	Total revenue allocated to remaining performance obligations as of December 31, 2019 will be recognized as revenue as follows: (in thousands) Next 12 months $ 569,751 Months 13-24 177,364 Months 25-36 93,097 Thereafter 30,531 Total revenue allocated to remaining performance obligations $ 870,743

Acquisitions (Tables)

Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2019
Business Combinations [Abstract]
Fair Value of Consideration Transferred	Fair Value of Consideration Transferred: (in thousands) LST Granta Design Other Acquisitions Total Cash $ 470,623 $ 208,736 $ 136,232 $ 815,591 Ansys common stock 307,173 — — 307,173 Total consideration transferred at fair value $ 777,796 $ 208,736 $ 136,232 $ 1,122,764 Fair Value of Consideration Transferred: (in thousands) OPTIS Cash $ 290,983
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	Recognized Amounts of Identifiable Assets Acquired and Liabilities Assumed: (in thousands) OPTIS Cash $ 7,957 Accounts receivable and other tangible assets 15,910 Developed software and core technologies (10-year weighted-average life) 47,597 Customer lists (12-year life) 41,303 Trade names (9-year weighted-average life) 10,749 Accounts payable and other liabilities (11,941 ) Deferred revenue (2,470 ) Net deferred tax liabilities (23,438 ) Total identifiable net assets $ 85,667 Goodwill $ 205,316 Recognized Amounts of Identifiable Assets Acquired and Liabilities Assumed: (in thousands) LST Granta Design Other Acquisitions Total Cash $ 8,520 $ 13,644 $ 6,231 $ 28,395 Accounts receivable and other tangible assets 20,568 6,941 10,746 38,255 Developed software and core technologies (10-year weighted-average life) 167,700 32,445 25,018 225,163 Customer lists (15-year weighted-average life) 25,900 20,016 15,743 61,659 Trade names (10-year weighted-average life) 10,600 4,579 2,051 17,230 Indemnification asset 34,039 — — 34,039 Accounts payable and other liabilities (3,721 ) (6,714 ) (6,425 ) (16,860 ) Deferred revenue (3,565 ) (1,426 ) (1,889 ) (6,880 ) Uncertain tax positions (34,039 ) — (257 ) (34,296 ) Net deferred tax liabilities (47,596 ) (9,822 ) (8,294 ) (65,712 ) Total identifiable net assets $ 178,406 $ 59,663 $ 42,924 $ 280,993 Goodwill $ 599,390 $ 149,073 $ 93,308 $ 841,771
Business Acquisition, Pro Forma Information	The table presented below reflects the impact of OPTIS from the date of acquisition to December 31, 2018. The operating loss does not include integration costs borne directly by us and our non-OPTIS subsidiaries as a result of the acquisition. (in thousands) Year Ended December 31, 2018 Revenue $ 18,532 Operating loss $ (5,462 ) (in thousands) Year Ended December 31, 2019 Revenue $ 44,079 Operating income $ 6,733

Other Receivables and Current_2

Other Receivables and Current Assets and Other Accrued Expenses and Liabilities (Tables)	12 Months Ended
	Dec. 31, 2019
Other Receivables and Current Assets and Other Accrued Expenses and Liabilities [Abstract]
Schedule of Other Receivables and Current Assets and Other Accrued Expenses and Liabilities	Our other receivables and current assets, and other accrued expenses and liabilities, comprise the following balances: December 31, (in thousands) 2019 2018 Receivables related to unrecognized revenue $ 177,679 $ 167,144 Income taxes receivable, including overpayments and refunds 26,672 13,709 Prepaid expenses and other current assets 45,268 35,260 Total other receivables and current assets $ 249,619 $ 216,113 Consumption, sales and VAT tax liabilities $ 36,398 $ 24,192 Accrued expenses and other current liabilities 106,549 75,367 Total other accrued expenses and liabilities $ 142,947 $ 99,559

Property and Equipment (Tables)

Property and Equipment (Tables)	12 Months Ended
	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Components Of Property and Equipment	Property and equipment consists of the following: December 31, (in thousands) Estimated Useful Lives 2019 2018 Equipment 1-15 years $ 105,428 $ 92,409 Computer software 1-5 years 33,878 35,053 Buildings and improvements 5-40 years 38,095 27,352 Leasehold improvements 1-17 years 19,876 15,782 Furniture 1-13 years 12,766 10,846 Land 2,696 1,759 Property and equipment, gross 212,739 183,201 Less: Accumulated depreciation (129,103 ) (121,546 ) Property and equipment, net $ 83,636 $ 61,655

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets (Finite-Lived)	Intangible assets are classified as follows: December 31, 2019 December 31, 2018 (in thousands) Gross Carrying Amount Accumulated Amortization Gross Carrying Amount Accumulated Amortization Finite-lived intangible assets: Developed software and core technologies $ 635,063 $ (332,622 ) $ 410,680 $ (314,730 ) Customer lists and contract backlog 269,629 (132,596 ) 209,031 (117,614 ) Trade names 154,259 (117,379 ) 137,225 (113,677 ) Total $ 1,058,951 $ (582,597 ) $ 756,936 $ (546,021 ) Indefinite-lived intangible asset: Trade name $ 357 $ 357
Intangible Assets (Indefinite-Lived)	Intangible assets are classified as follows: December 31, 2019 December 31, 2018 (in thousands) Gross Carrying Amount Accumulated Amortization Gross Carrying Amount Accumulated Amortization Finite-lived intangible assets: Developed software and core technologies $ 635,063 $ (332,622 ) $ 410,680 $ (314,730 ) Customer lists and contract backlog 269,629 (132,596 ) 209,031 (117,614 ) Trade names 154,259 (117,379 ) 137,225 (113,677 ) Total $ 1,058,951 $ (582,597 ) $ 756,936 $ (546,021 ) Indefinite-lived intangible asset: Trade name $ 357 $ 357
Estimated Future Amortization Expense for Intangible Assets	As of December 31, 2019 , estimated future amortization expense for the intangible assets reflected above is as follows: (in thousands) 2020 $ 54,735 2021 53,231 2022 53,548 2023 52,474 2024 50,530 Thereafter 211,836 Total intangible assets subject to amortization, net 476,354 Indefinite-lived trade name 357 Other intangible assets, net $ 476,711
Changes in Goodwill	The changes in goodwill during the years ended December 31, 2019 and 2018 were as follows: (in thousands) 2019 2018 Beginning balance - January 1 $ 1,572,455 $ 1,378,553 Acquisitions and adjustments (1) 842,588 204,381 Currency translation (1,763 ) (10,479 ) Ending balance - December 31 $ 2,413,280 $ 1,572,455 (1) In accordance with the accounting for business combinations, we 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 we obtained new information about facts and circumstances that existed as of the acquisition date that, if known, would have affected the measurement of the amounts recognized as of that date.

Fair Value Measurement (Tables)

Fair Value Measurement (Tables)	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value of Assets and Liabilities Measured on Recurring Basis	The following tables provide the assets carried at fair value and measured on a recurring basis: Fair Value Measurements at Reporting Date Using: (in thousands) December 31, 2019 Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets Cash equivalents $ 322,455 $ 322,455 $ — $ — Short-term investments $ 288 $ — $ 288 $ — Deferred compensation plan investments $ 1,110 $ 1,110 $ — $ — Fair Value Measurements at Reporting Date Using: (in thousands) December 31, 2018 Quoted Prices in Active Markets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Assets Cash equivalents $ 446,055 $ 446,055 $ — $ — Short-term investments $ 225 $ — $ 225 $ — Deferred compensation plan investments $ 1,646 $ 1,646 $ — $ —

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Schedule of Lease Cost	The components of our global lease cost reflected in the consolidated statements of income for the year ended December 31, 2019 are as follows: (in thousands) Lease liability cost $ 22,507 Variable lease cost not included in the lease liability (1) 3,754 Total lease cost $ 26,261 (1) Variable lease cost includes common area maintenance, property taxes, utilities and fluctuations in rent due to a change in an index or rate.
Lessee, Operating Lease Other Information	Other information related to operating leases for the year ended December 31, 2019 is as follows: (in thousands) Cash paid for amounts included in the measurement of the lease liability: Operating cash flows from operating leases $ (20,031 ) Right-of-use assets obtained in exchange for new operating lease liabilities $ 35,191
Schedule of Maturity of Operating Lease Liabilities	The maturity schedule of the operating lease liabilities as of December 31, 2019 is as follows: (in thousands) 2020 $ 21,617 2021 19,439 2022 16,616 2023 12,513 2024 12,421 Thereafter 46,159 Total future lease payments 128,765 Less: Present value adjustment (18,838 ) Present value of future lease payments (1) $ 109,927 (1) Includes the current portion of operating lease liabilities of $18.2 million , which is reflected in other accrued expenses and liabilities in the consolidated balance sheets.
Schedule of Future Minimum Rental Payments for Operating Leases	The future minimum lease payments under ASC 840, including termination fees, under noncancellable operating leases for office space in effect at December 31, 2018 were as follows: (in thousands) 2019 $ 16,354 2020 12,469 2021 10,177 2022 8,523 2023 6,809 Thereafter 14,267 Total $ 68,599

Debt (Table)

Debt (Table)	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Schedule of Maturities of Debt	As of December 31, 2019 , scheduled maturities of total debt for each of the five succeeding fiscal years is as follows: (in thousands) 2020 (1) $ — 2021 — 2022 25,000 2023 50,000 2024 425,000 Total $ 500,000 (1) We repaid $75.0 million of the unsecured term loan in January 2020 prior to its scheduled maturity date. As such, the payment is reflected as current on our consolidated balance sheet but not in the table above.

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Components Of Income Before Income Taxes	Income before income taxes included the following components: Year Ended December 31, (in thousands) 2019 2018 2017 Domestic $ 448,271 $ 455,478 $ 344,447 Foreign 74,312 31,607 51,247 Total $ 522,583 $ 487,085 $ 395,694
Components Of Provision For Income Taxes	The provision for income taxes was composed of the following: Year Ended December 31, (in thousands) 2019 2018 2017 Current: Federal $ 44,824 $ 58,138 $ 112,414 State 9,554 12,888 7,879 Foreign 31,421 30,359 18,843 Deferred: Federal (8,833 ) (20,764 ) (7,387 ) State (965 ) (2,901 ) (584 ) Foreign (4,713 ) (10,010 ) 5,278 Total $ 71,288 $ 67,710 $ 136,443
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 was as follows: Year Ended December 31, 2019 2018 2017 Federal statutory tax rate 21.0 % 21.0 % 35.0 % State income taxes, net of federal benefit 1.5 1.5 1.1 Foreign rate differential 0.8 0.8 0.1 Uncertain tax positions (0.2 ) 0.5 0.3 U.S. tax reform enactment (0.4 ) 0.2 4.5 Valuation allowance release (1.3 ) — — Domestic production activity benefit — — (2.6 ) Benefit from entity structuring activities — (1.4 ) — Research and development credits (2.2 ) (2.3 ) (1.4 ) Stock-based compensation (3.1 ) (3.3 ) (3.1 ) Foreign-derived intangible income deduction (3.8 ) (3.9 ) — Other 1.3 0.8 0.6 13.6 % 13.9 % 34.5 %
Components Of Deferred Tax Assets And Liabilities	The components of deferred tax assets and liabilities are as follows: December 31, (in thousands) 2019 2018 Deferred tax assets: Net operating loss carryforwards $ 35,044 $ 39,290 Operating lease liabilities 26,628 — Stock-based compensation 24,254 20,464 Uncertain tax positions 19,227 17,823 Employee benefits 9,392 15,048 Research and development credits 5,865 5,951 Other 6,309 4,121 Valuation allowance (17,524 ) (21,676 ) Total deferred tax assets 109,195 81,021 Deferred tax liabilities: Other intangible assets (99,193 ) (38,787 ) Operating lease right-of-use assets (25,648 ) — Accounting method change (21,396 ) (31,626 ) Deferred revenue (13,744 ) (12,021 ) Property and equipment (3,780 ) (2,034 ) Total deferred tax liabilities (163,761 ) (84,468 ) Net deferred tax liabilities $ (54,566 ) $ (3,447 )
Reconciliation Of Unrecognized Tax Benefits	The following is a reconciliation of the total amounts of unrecognized tax benefits: Year Ended December 31, (in thousands) 2019 2018 2017 Unrecognized tax benefit as of January 1 $ 22,827 $ 19,657 $ 15,209 Gross increases—acquisitions 26,914 — — Gross increases—tax positions in prior period 207 1,229 905 Gross decreases—tax positions in prior period (1,743 ) (376 ) (765 ) Gross increases—tax positions in current period 3,563 4,014 3,757 Reductions due to a lapse of the applicable statute of limitations (2,230 ) (994 ) (847 ) Changes due to currency fluctuation (453 ) (703 ) 1,414 Settlements — — (16 ) Unrecognized tax benefit as of December 31 $ 49,085 $ 22,827 $ 19,657

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2019
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, 2019 , 2018 and 2017 is as follows: Year Ended December 31, (in thousands, except per share amounts) 2019 2018 2017 Cost of sales: Software licenses $ — $ — $ 969 Maintenance and service 8,494 5,224 2,533 Operating expenses: Selling, general and administrative 60,639 47,099 30,817 Research and development 47,057 31,023 18,835 Stock-based compensation expense before taxes 116,190 83,346 53,154 Related income tax benefits (47,454 ) (34,518 ) (20,503 ) Stock-based compensation expense, net of taxes $ 68,736 $ 48,828 $ 32,651 Net impact on earnings per share: Basic earnings per share $ (0.82 ) $ (0.58 ) $ (0.38 ) Diluted earnings per share $ (0.80 ) $ (0.57 ) $ (0.38 )
Summary Of Stock Options	Information regarding stock option transactions is summarized below: Year Ended December 31, 2019 2018 2017 (options in thousands) Options Weighted- Average Exercise Price Options Weighted- Average Exercise Price Options Weighted- Average Exercise Price Outstanding, beginning of year 1,484 $ 62.80 2,170 $ 59.17 3,136 $ 56.37 Granted — $ — — $ — — $ — Exercised (495 ) $ 53.53 (679 ) $ 50.92 (956 ) $ 49.78 Forfeited (5 ) $ 64.21 (7 ) $ 86.28 (10 ) $ 80.92 Outstanding, end of year 984 $ 67.49 1,484 $ 62.80 2,170 $ 59.17 Vested and Exercisable, end of year 924 $ 65.71 1,347 $ 59.69 1,930 $ 55.11 Nonvested 60 $ 94.77 137 $ 93.44 240 $ 91.71 2019 2018 2017 Weighted Average Remaining Contractual Term (in years) Outstanding 3.18 3.55 4.10 Vested and Exercisable 2.95 3.14 3.57 Nonvested 6.71 7.60 8.30 Aggregate Intrinsic Value (in thousands) Exercised $ 72,098 $ 78,648 $ 58,472 Outstanding $ 186,926 $ 118,908 $ 191,895 Vested and Exercisable $ 177,111 $ 112,133 $ 178,456 Nonvested $ 9,815 $ 6,775 $ 13,439 Compensation Expense - Stock Options (in thousands) $ 1,709 $ 2,006 $ 2,948
Summary Of Restricted Stock Units	Information regarding all employee RSU transactions is summarized below: Year Ended December 31, 2019 2018 2017 (RSUs in thousands) RSUs Weighted- Average Grant Date Fair Value RSUs Weighted- Average Grant Date Fair Value RSUs Weighted- Average Grant Date Fair Value Nonvested, beginning of year 1,522 $ 129.96 1,361 $ 100.66 906 $ 86.45 Granted (1) 843 $ 192.37 681 $ 163.67 866 $ 109.67 Performance adjustment (2) 74 $ 167.87 76 $ 151.52 35 $ 98.29 Vested (704 ) $ 125.84 (524 ) $ 101.38 (341 ) $ 88.58 Forfeited (117 ) $ 140.43 (72 ) $ 125.29 (105 ) $ 90.80 Nonvested, end of year 1,618 $ 165.26 1,522 $ 129.96 1,361 $ 100.66 (1) Includes all RSUs granted during the year. RSUs with operating performance conditions are issued annually and have one or three performance cycles. Performance conditions are assigned at the beginning of each performance cycle and are reflected as grants at target at that time. (2) RSUs with a market or performance condition are granted at target and vest based on achievement of the market or operating performance and service conditions. The actual number of RSUs issued may be more or less than the target RSUs depending on the achievement of the market or operating performance conditions.
Summary Of Deferred Stock Awards To Non-Employee Directors	Information regarding deferred stock awards to non-employee Directors is summarized below: Year Ended December 31, 2019 Diversified Undiversified Total Deferred Awards Outstanding, beginning of year 12,250 120,449 132,699 Shares Diversified 13,348 (13,348 ) — Shares Issued Upon Retirement (20,000 ) (47,020 ) (67,020 ) Deferred Awards Outstanding, end of year 5,598 60,081 65,679
Employee Stock Option
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Information Regarding Stock Options Outstanding	Information regarding stock options outstanding as of December 31, 2019 is summarized below: (options in thousands) Options Outstanding Options Exercisable Options Unvested Range of Exercise Prices Options Weighted- Weighted- Options Weighted- Average Remaining Contractual Life (years) Weighted- Options Weighted- Average Remaining Contractual Life (years) Weighted- Average Exercise Price $11.99 - $48.97 181 1.01 $ 43.29 181 1.01 $ 43.29 — 0.00 $ — $58.67 267 1.87 $ 58.67 267 1.87 $ 58.67 — 0.00 $ — $67.44 280 2.87 $ 67.44 280 2.87 $ 67.44 — 0.00 $ — $76.31 - $95.09 256 6.44 $ 93.89 196 6.36 $ 93.62 60 6.71 $ 94.77
Restricted Stock Units (RSUs)
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Assumptions To Estimate Fair Value Of Stock Awards	The determination of the fair values of the awards was affected by the grant date and several variables, each of which has been identified in the chart below: Year Ended December 31, Assumptions used in Monte Carlo lattice pricing model 2019 2018 2017 Risk-free interest rate 2.5% 2.4% 1.5% Expected dividend yield —% —% —% Expected volatility—Ansys stock price 23% 21% 19% Expected volatility—Nasdaq Composite Index 16% 15% 15% Expected term 2.8 years 2.8 years 2.8 years Correlation factor 0.71 0.65 0.70 Weighted average fair value per share $238.99 $191.76 $120.94

Stock Repurchase Program (Table

Stock Repurchase Program (Tables)	12 Months Ended
	Dec. 31, 2019
Class of Stock Disclosures [Abstract]
Stock Repurchase Program	Under our stock repurchase program, we repurchased shares as follows: Year Ended December 31, (in thousands, except per share data) 2019 2018 2017 Number of shares repurchased 330 1,674 2,750 Average price paid per share $ 179.41 $ 161.12 $ 122.20 Total cost $ 59,116 $ 269,801 $ 336,042

Geographic Information (Tables)

Geographic Information (Tables)	12 Months Ended
	Dec. 31, 2019
Segments, Geographical Areas [Abstract]
Revenue By Geographic Area	Revenue by geographic area was as follows: Year Ended December 31, (in thousands) 2019 2018 2017 United States $ 637,916 $ 506,335 $ 417,343 Japan 162,154 145,951 126,097 Germany 158,809 140,506 108,211 South Korea 90,082 72,724 63,011 France 68,551 67,657 53,672 China 64,725 57,567 54,415 Other EMEA 211,193 193,317 166,472 Other international 122,462 109,579 106,029 Total revenue $ 1,515,892 $ 1,293,636 $ 1,095,250
Property and Equipment by Geographic Area	Property and equipment by geographic area was as follows: December 31, (in thousands) 2019 2018 United States $ 59,473 $ 46,605 India 5,660 4,176 Germany 4,237 2,158 United Kingdom 4,194 1,238 Other EMEA 5,532 3,724 Other international 4,540 3,754 Total property and equipment, net $ 83,636 $ 61,655

Unconditional Purchase Obliga_2

Unconditional Purchase Obligations (Tables)	12 Months Ended
	Dec. 31, 2019
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, 2019 are as follows: (in thousands) 2020 $ 37,183 2021 14,034 2022 10,689 2023 6,212 2024 3,264 Total $ 71,382

Restructuring (Tables)

Restructuring (Tables)	12 Months Ended
	Dec. 31, 2019
Restructuring and Related Activities [Abstract]
Restructuring and Related Costs	We incurred related restructuring charges as follows: (in thousands) Gross Net of Tax Q4 2016 $ 3,419 $ 2,355 Q1 2017 9,273 6,176 Q2 2017 2,000 1,435 Q3 2017 466 331 Total restructuring charges $ 15,158 $ 10,297

Organization - Additional Infor

Organization - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2019Segment
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of operating segments	1

Summary Of Significant Accoun_3

Summary Of Significant Accounting Policies - Additional Information (Details)	12 Months Ended
	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Jan. 01, 2019USD ($)
Operating lease right-of-use assets	$ 105,671,000			$ 90,900,000
Operating lease liabilities	109,927,000			$ 92,500,000
Impact of ASU 2018-15 adoption	$ 2,500,000	$ 1,400,000	$ 2,800,000
Lease license to license revenue	50.00%
Lease license to maintenance revenue	50.00%
Amortization of intangible assets	$ 36,900,000	40,800,000	49,800,000
Provisions for doubtful accounts	2,928,000	1,577,000	1,474,000
Net foreign exchange losses	$ (2,500,000)	$ (3,100,000)	$ (1,900,000)
Minimum
Semiconductor product licenses, term	24 months
Property and equipment, estimated useful lives (years)	1 year
Finite-lived intangible asset, useful life	2 years
Maximum
Semiconductor product licenses, term	36 months
Property and equipment, estimated useful lives (years)	40 years
Finite-lived intangible asset, useful life	17 years
Customer Concentration Risk
Number of customers with more than five percent of revenue	0	0	0

Summary Of Significant Accoun_4

Summary Of Significant Accounting Policies (Summary Of Cash And Cash Equivalents) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Cash accounts, Amount	$ 549,639	$ 331,084
Money market funds, Amount	322,455	446,055
Total	$ 872,094	$ 777,139
Cash
Percent Of Cash And Cash Equivalents	63.00%	42.60%
Money Market Funds
Percent Of Cash And Cash Equivalents	37.00%	57.40%

Summary Of Significant Accoun_5

Summary Of Significant Accounting Policies (Schedule Of Risk Concentration) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Concentration Risk [Line Items]
Total	$ 872,094	$ 777,139
Customer Concentration Risk
Concentration Risk [Line Items]
Channel partner concentration risk, percentage	23.00%	22.00%	25.00%
Credit Concentration Risk
Concentration Risk [Line Items]
Cash and cash equivalents held in excess of deposit insurance, foreign and domestic	$ 855,721	$ 754,163
Largest balance of cash and cash equivalents held with one financial institution, foreign and domestic	$ 330,551	$ 452,166
1st Largest Channel Partner | Customer Concentration Risk
Concentration Risk [Line Items]
Channel partner concentration risk, percentage	4.00%	4.00%	5.00%
2nd Largest Channel Partner | Customer Concentration Risk
Concentration Risk [Line Items]
Channel partner concentration risk, percentage	2.00%	2.00%	2.00%
United States | Credit Concentration Risk
Concentration Risk [Line Items]
Total	$ 626,433	$ 616,249
Foreign | Credit Concentration Risk
Concentration Risk [Line Items]
Total	$ 245,661	$ 160,890

Summary Of Significant Accoun_6

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, 2019	Dec. 31, 2018	Dec. 31, 2017
Accounting Policies [Abstract]
Net income	$ 451,295	$ 419,375	$ 259,251
Weighted average shares outstanding - basic	84,259	83,973	84,988
Dilutive effect of stock plans	1,666	1,940	1,866
Weighted average shares outstanding - diluted	85,925	85,913	86,854
Basic earnings per share	$ 5.36	$ 4.99	$ 3.05
Diluted earnings per share	$ 5.25	$ 4.88	$ 2.98
Anti-dilutive shares	14	7	84

Revenue from Contracts with C_3

Revenue from Contracts with Customers - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Jan. 01, 2018
Cumulative effect of new accounting principle in period of adoption			$ 183,120
Lease license to license revenue	50.00%
Amount of revenue recognized from beginning deferred revenue and backlog	$ 475,900	$ 387,200
Gross impact
Cumulative effect of new accounting principle in period of adoption			$ 242,400

Disaggregation of Revenue (Deta

Disaggregation of Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement [Line Items]
Total revenue	$ 1,515,892	$ 1,293,636	$ 1,095,250
Lease license
Statement [Line Items]
Total revenue	406,043	275,619	376,886
Perpetual license
Statement [Line Items]
Total revenue	293,587	301,098	248,078
Software licenses
Statement [Line Items]
Total revenue	699,630	576,717	624,964
Maintenance
Statement [Line Items]
Total revenue	760,574	676,883	440,428
Service
Statement [Line Items]
Total revenue	55,688	40,036	29,858
Maintenance and service
Statement [Line Items]
Total revenue	$ 816,262	$ 716,919	$ 470,286
Direct revenue, as a percentage of total revenue
Statement [Line Items]
Concentration risk, percentage	77.10%	77.60%	75.20%
Indirect revenue, as a percentage of total revenue
Statement [Line Items]
Concentration risk, percentage	22.90%	22.40%	24.80%

Changes in Deferred Revenue (De

Changes in Deferred Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Movement in Deferred Revenue [Roll Forward]
Beginning balance	$ 343,174	$ 299,730
Acquired deferred revenue	6,880	2,470
Deferral of revenue	1,532,549	1,339,964
Recognition of deferred revenue	(1,515,892)	(1,293,636)
Currency translation	(1,437)	(5,354)
Ending balance	$ 365,274	$ 343,174

Remaining Performance Obligatio

Remaining Performance Obligations, Expected Timing of Satisfaction (Details) $ in Thousands	Dec. 31, 2019USD ($)
Revenue from Contract with Customer [Abstract]
Revenue, remaining performance obligation, amount	$ 870,743
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue from Contract with Customer [Abstract]
Revenue, remaining performance obligation, amount	$ 569,751
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	12 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue from Contract with Customer [Abstract]
Revenue, remaining performance obligation, amount	$ 177,364
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	12 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue from Contract with Customer [Abstract]
Revenue, remaining performance obligation, amount	$ 93,097
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	12 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue from Contract with Customer [Abstract]
Revenue, remaining performance obligation, amount	$ 30,531
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period

Acquisitions - Additional Infor

Acquisitions - Additional Information (Detail) - USD ($) $ / shares in Units, shares in Thousands	Nov. 01, 2019	Feb. 01, 2019	May 02, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Total consideration transferred at fair value				$ 1,122,764,000
Fair value of common stock issued as consideration in connection with acquisitions				307,173,000	$ 0	$ 0
Acquisition costs				6,600,000
Uncertain tax positions				34,296,000
Livermore Software Technology Corporation
Percentage of shares acquired	100.00%
Total consideration transferred at fair value	$ 777,796,000
Payments to acquire businesses, gross	$ 470,600,000
Business acquisition, equity interest issued or Issuable, number of shares	1,400
Business acquisition, share price	$ 220.74
Fair value of common stock issued as consideration in connection with acquisitions	$ 307,173,000
Uncertain tax positions	$ 34,039,000
Granta Design
Percentage of shares acquired		100.00%
Total consideration transferred at fair value		$ 208,736,000
Payments to acquire businesses, gross		208,700,000
Uncertain tax positions		$ 0
OPTIS
Percentage of shares acquired			100.00%
Total consideration transferred at fair value			$ 290,983,000
Payments to acquire businesses, gross			$ 291,000,000
Goodwill, period increase (decrease)				2,600,000
Series of Individually Immaterial Business Acquisitions
Total consideration transferred at fair value				136,232,000
Payments to acquire businesses, gross				136,200,000		$ 67,000,000
Uncertain tax positions				$ 257,000

Acquisitions Fair Value of Cons

Acquisitions Fair Value of Consideration Transferred 2019 (Details) - USD ($) $ in Thousands	Nov. 01, 2019	Feb. 01, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash			$ 815,591
Fair value of common stock issued as consideration in connection with acquisitions			307,173	$ 0	$ 0
Total consideration transferred at fair value			1,122,764
Livermore Software Technology Corporation
Cash	$ 470,623
Fair value of common stock issued as consideration in connection with acquisitions	307,173
Total consideration transferred at fair value	$ 777,796
Granta Design
Cash		$ 208,736
Total consideration transferred at fair value		$ 208,736
Other Acquisitions
Cash			136,232
Total consideration transferred at fair value			$ 136,232

Acquisitions Recognized Amounts

Acquisitions Recognized Amounts of Identifiable Assets Acquired and Liabilities Assumed 2019 (Details) - USD ($)	Dec. 31, 2019	Nov. 01, 2019	Feb. 01, 2019
Business Acquisition [Line Items]
Cash	$ 28,395,000
Accounts receivable and other tangible assets	38,255,000
Indemnification asset	34,039,000
Accounts payable and other liabilities	(16,860,000)
Deferred revenue	(6,880,000)
Uncertain tax positions	(34,296,000)
Net deferred tax liabilities	(65,712,000)
Total identifiable net assets	280,993,000
Goodwill	841,771,000
Developed Software and Core Technologies
Business Acquisition [Line Items]
Finite-lived intangible assets	225,163,000
Customer Lists
Business Acquisition [Line Items]
Finite-lived intangible assets	61,659,000
Trade Names
Business Acquisition [Line Items]
Finite-lived intangible assets	17,230,000
Livermore Software Technology Corporation
Business Acquisition [Line Items]
Cash		$ 8,520,000
Accounts receivable and other tangible assets		20,568,000
Indemnification asset		34,039,000
Accounts payable and other liabilities		(3,721,000)
Deferred revenue		(3,565,000)
Uncertain tax positions		(34,039,000)
Net deferred tax liabilities		(47,596,000)
Total identifiable net assets		178,406,000
Goodwill		599,390,000
Livermore Software Technology Corporation | Developed Software and Core Technologies
Business Acquisition [Line Items]
Finite-lived intangible assets		167,700,000
Livermore Software Technology Corporation | Customer Lists
Business Acquisition [Line Items]
Finite-lived intangible assets		25,900,000
Livermore Software Technology Corporation | Trade Names
Business Acquisition [Line Items]
Finite-lived intangible assets		$ 10,600,000
Granta Design
Business Acquisition [Line Items]
Cash			$ 13,644,000
Accounts receivable and other tangible assets			6,941,000
Indemnification asset			0
Accounts payable and other liabilities			(6,714,000)
Deferred revenue			(1,426,000)
Uncertain tax positions			0
Net deferred tax liabilities			(9,822,000)
Total identifiable net assets			59,663,000
Goodwill			149,073,000
Granta Design | Developed Software and Core Technologies
Business Acquisition [Line Items]
Finite-lived intangible assets			32,445,000
Granta Design | Customer Lists
Business Acquisition [Line Items]
Finite-lived intangible assets			20,016,000
Granta Design | Trade Names
Business Acquisition [Line Items]
Finite-lived intangible assets			$ 4,579,000
Other Acquisitions
Business Acquisition [Line Items]
Cash	6,231,000
Accounts receivable and other tangible assets	10,746,000
Indemnification asset	0
Accounts payable and other liabilities	(6,425,000)
Deferred revenue	(1,889,000)
Uncertain tax positions	(257,000)
Net deferred tax liabilities	(8,294,000)
Total identifiable net assets	42,924,000
Goodwill	93,308,000
Other Acquisitions | Developed Software and Core Technologies
Business Acquisition [Line Items]
Finite-lived intangible assets	25,018,000
Other Acquisitions | Customer Lists
Business Acquisition [Line Items]
Finite-lived intangible assets	15,743,000
Other Acquisitions | Trade Names
Business Acquisition [Line Items]
Finite-lived intangible assets	$ 2,051,000

Acquisitions Pro Forma Informat

Acquisitions Pro Forma Information 2019 (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenue	$ 1,515,892	$ 1,293,636	$ 1,095,250
Operating income	515,040	$ 476,574	$ 390,728
2019 Acquisitions
Revenue	44,079
Operating income	$ 6,733

Fair Value of Consideration Tra

Fair Value of Consideration Transferred 2018 (Details) - USD ($) $ in Thousands	May 02, 2018	Dec. 31, 2019
Cash		$ 1,122,764
OPTIS
Cash	$ 290,983

Recognized Amounts of Identifia

Recognized Amounts of Identifiable Assets Acquired and Liabilities Assumed 2018 (Details) - USD ($) $ in Thousands	Dec. 31, 2019	May 02, 2018
Business Acquisition [Line Items]
Cash	$ 28,395
Accounts receivable and other tangible assets	38,255
Accounts payable and other liabilities	(16,860)
Deferred revenue	(6,880)
Net deferred tax liabilities	(65,712)
Total identifiable net assets	280,993
Goodwill	841,771
Developed Software and Core Technologies
Business Acquisition [Line Items]
Finite-lived intangible assets	225,163
Customer Lists
Business Acquisition [Line Items]
Finite-lived intangible assets	61,659
Trade Names
Business Acquisition [Line Items]
Finite-lived intangible assets	$ 17,230
OPTIS
Business Acquisition [Line Items]
Cash		$ 7,957
Accounts receivable and other tangible assets		15,910
Accounts payable and other liabilities		(11,941)
Deferred revenue		(2,470)
Net deferred tax liabilities		(23,438)
Total identifiable net assets		85,667
Goodwill		205,316
OPTIS | Developed Software and Core Technologies
Business Acquisition [Line Items]
Finite-lived intangible assets		47,597
OPTIS | Customer Lists
Business Acquisition [Line Items]
Finite-lived intangible assets		41,303
OPTIS | Trade Names
Business Acquisition [Line Items]
Finite-lived intangible assets		$ 10,749

Pro Forma Information 2018 (Det

Pro Forma Information 2018 (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenue	$ 1,515,892	$ 1,293,636	$ 1,095,250
Operating income (loss)	$ 515,040	476,574	$ 390,728
OPTIS
Revenue		18,532
Operating income (loss)		$ (5,462)

Valuation Assumptions and Weigh

Valuation Assumptions and Weighted-Average Useful Life (Details)	May 02, 2018	Dec. 31, 2019	Nov. 01, 2019	Feb. 01, 2019
Developed Software and Core Technologies
Finite-lived intangible asset, useful life		10 years
Trade Names
Finite-lived intangible asset, useful life		10 years
Customer Lists
Finite-lived intangible asset, useful life		15 years
Livermore Software Technology Corporation | Developed Software and Core Technologies
Royalty Rate			50.00%
Discount Rate			10.00%
Livermore Software Technology Corporation | Trade Names
Royalty Rate			2.00%
Discount Rate			10.00%
Livermore Software Technology Corporation | Customer Lists
Discount Rate			11.00%
Attrition Rate			10.00%
Granta Design | Developed Software and Core Technologies
Discount Rate				12.50%
Granta Design | Trade Names
Royalty Rate				2.00%
Discount Rate				14.00%
Granta Design | Customer Lists
Discount Rate				12.50%
Attrition Rate				10.00%
Granta Design | Minimum | Developed Software and Core Technologies
Royalty Rate				8.00%
Granta Design | Maximum | Developed Software and Core Technologies
Royalty Rate				10.00%
OPTIS | Developed Software and Core Technologies
Finite-lived intangible asset, useful life	10 years
OPTIS | Trade Names
Finite-lived intangible asset, useful life	9 years
OPTIS | Customer Lists
Finite-lived intangible asset, useful life	12 years

Other Receivables and Current_3

Other Receivables and Current Assets and Other Accrued Expenses and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Other Receivables and Current Assets and Other Accrued Expenses and Liabilities [Abstract]
Receivables related to unrecognized revenue	$ 177,679	$ 167,144
Income taxes receivable, including overpayments and refunds	26,672	13,709
Prepaid expenses and other current assets	45,268	35,260
Total other receivables and current assets	249,619	216,113
Consumption, sales and VAT tax liabilities	36,398	24,192
Accrued expenses and other current liabilities	106,549	75,367
Total other accrued expenses and liabilities	$ 142,947	$ 99,559

Property and Equipment - Additi

Property and Equipment - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Abstract]
Depreciation expense related to property and equipment	$ 23.6	$ 18.4	$ 17.9

Property and Equipment (Compone

Property and Equipment (Components Of Property and Equipment) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 212,739	$ 183,201
Less: Accumulated depreciation	(129,103)	(121,546)
Property and equipment, net	83,636	61,655
Equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	105,428	92,409
Computer Software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	33,878	35,053
Building and Building Improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	38,095	27,352
Leasehold Improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	19,876	15,782
Furniture
Property, Plant and Equipment [Line Items]
Property and equipment, gross	12,766	10,846
Land
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 2,696	$ 1,759
Minimum
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives (years)	1 year
Minimum | Equipment
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives (years)	1 year
Minimum | Computer Software
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives (years)	1 year
Minimum | Building and Building Improvements
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives (years)	5 years
Minimum | Leasehold Improvements
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives (years)	1 year
Minimum | Furniture
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives (years)	1 year
Maximum
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives (years)	40 years
Maximum | Equipment
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives (years)	15 years
Maximum | Computer Software
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives (years)	5 years
Maximum | Building and Building Improvements
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives (years)	40 years
Maximum | Leasehold Improvements
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives (years)	17 years
Maximum | Furniture
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful lives (years)	13 years

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization of intangible assets	$ 36,900,000	$ 40,800,000	$ 49,800,000

Intangible Assets (Detail)

Intangible Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Intangible Assets [Line Items]
Amortized intangible assets, gross carrying amount	$ 1,058,951	$ 756,936
Amortized intangible assets, accumulated amortization	(582,597)	(546,021)
Indefinite-lived trade name	357
Trade Names
Intangible Assets [Line Items]
Indefinite-lived trade name	357	357
Developed Software and Core Technologies
Intangible Assets [Line Items]
Amortized intangible assets, gross carrying amount	635,063	410,680
Amortized intangible assets, accumulated amortization	(332,622)	(314,730)
Customer Lists
Intangible Assets [Line Items]
Amortized intangible assets, gross carrying amount	269,629	209,031
Amortized intangible assets, accumulated amortization	(132,596)	(117,614)
Trade Names
Intangible Assets [Line Items]
Amortized intangible assets, gross carrying amount	154,259	137,225
Amortized intangible assets, accumulated amortization	$ (117,379)	$ (113,677)

Estimated Future Amortization E

Estimated Future Amortization Expense for Intangible Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
2020	$ 54,735
2021	53,231
2022	53,548
2023	52,474
2024	50,530
Thereafter	211,836
Total intangible assets subject to amortization, net	476,354
Indefinite-lived trade name	357
Other intangible assets, net	$ 476,711	$ 211,272

Changes in Goodwill (Detail)

Changes in Goodwill (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Goodwill [Roll Forward]
Beginning balance	$ 1,572,455	$ 1,378,553
Acquisitions and adjustments	842,588	204,381
Currency translation	(1,763)	(10,479)
Ending balance	$ 2,413,280	$ 1,572,455

Fair Value of Assets and Liabil

Fair Value of Assets and Liabilities Measured on Recurring Basis (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	$ 322,455	$ 446,055
Short-term investments	288	225
Deferred compensation plan investments	1,110	1,646
Quoted Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	322,455	446,055
Short-term investments	0	0
Deferred compensation plan investments	1,110	1,646
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	288	225
Deferred compensation plan investments	0	0
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Short-term investments	0	0
Deferred compensation plan investments	$ 0	$ 0

Fair Value Measurement - Additi

Fair Value Measurement - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2019
Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments maturity	3 months
Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Short-term investments maturity	1 year

Leases - Additional Information

Leases - Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)ft²	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Lessee, Lease, Description [Line Items]
Lease cost	$ 26,261	$ 21,300	$ 18,400
Operating lease, weighted average remaining lease term	7 years 8 months 12 days
Operating lease, weighted average discount rate, percent	3.70%
Current portion of operating lease liabilities	$ 18,200
Operating office lease liabilities that have not yet commenced	$ 16,300
Lessee, operating lease, lease not yet commenced, term of contract	7 years 2 months 12 days
Canonsburg Office, New Company Headquarters | Lease Agreement Effective September 14, 2012
Lessee, Lease, Description [Line Items]
Area of real estate property | ft²	186,000
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

Leases Schedule of Lease Cost (

Leases Schedule of Lease Cost (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Leases [Abstract]
Lease liability cost	$ 22,507
Variable lease cost not included in the lease liability	3,754
Total lease cost	$ 26,261	$ 21,300	$ 18,400

Leases Lessee, Operating Lease

Leases Lessee, Operating Lease Other Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)
Leases [Abstract]
Operating cash flows from operating leases	$ (20,031)
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 35,191

Leases Schedule of Maturity of

Leases Schedule of Maturity of Operating Lease Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Jan. 01, 2019
Leases [Abstract]
2020	$ 21,617
2021	19,439
2022	16,616
2023	12,513
2024	12,421
Thereafter	46,159
Total future lease payments	128,765
Present value adjustment	(18,838)
Present value of future lease payments	$ 109,927	$ 92,500

Leases Schedule of Future Minim

Leases Schedule of Future Minimum Rental Payments for Operating Leases (Detail) $ in Thousands	Dec. 31, 2018USD ($)
Leases [Abstract]
2019	$ 16,354
2020	12,469
2021	10,177
2022	8,523
2023	6,809
Thereafter	14,267
Future minimum lease payments	$ 68,599

Debt (Detail)

Debt (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2019	Nov. 01, 2019
Line of Credit Facility [Line Items]
Weighted-average interest rate at a point in time	2.964%
Consolidated leverage ratio	3.50
Consolidated leverage ratio increased	4
Qualified acquisition amount	$ 250,000,000
Outstanding borrowings under the credit agreement	0
Term loan	$ 498,500,000	$ 500,000,000
Term loan principal repayment rate, initial	1.25%
Term loan principal repayment rate, increased	2.50%
Unamortized debt issuance cost	$ 1,500,000
Current portion of long-term debt	75,000,000
Revolving Credit Facility
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity	500,000,000
Letter of Credit
Line of Credit Facility [Line Items]
Line of credit facility, maximum borrowing capacity	$ 50,000,000
Base Rate
Line of Credit Facility [Line Items]
Debt instrument, basis spread on federal funds rate	0.50%
Debt instrument, basis spread on eurodollar rate	1.00%
Base Rate | Minimum
Line of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate	0.125%
Base Rate | Maximum
Line of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate	0.75%
Eurodollar | Minimum
Line of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate	1.125%
Eurodollar | Maximum
Line of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate	1.75%

Schedule of Maturities of Debt

Schedule of Maturities of Debt (Details) $ in Thousands	Dec. 31, 2019USD ($)
Debt Disclosure [Abstract]
2020	$ 0
2021	0
2022	25,000
2023	50,000
2024	425,000
Total	$ 500,000

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	12 Months Ended			27 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2019
Income Tax Contingency [Line Items]
Federal statutory tax rate	21.00%	21.00%	35.00%
Effective income tax rate reconciliation, change in enacted tax rate, amount			$ 1,900,000
Effective income tax rate reconciliation, repatriation of foreign earnings, amount	$ (1,800,000)	$ 900,000	16,000,000	$ 15,100,000
Cumulative temporary difference, permanently reinvested earnings	(32,800,000)
Foreign earnings repatriated		144,300,000
Valuation allowance, deferred tax asset, increase (decrease), amount	(4,200,000)
Effective income tax rate reconciliation, GILTI, amount	600,000	400,000
Valuation allowance, deferred taxes, released	6,700,000
Deferred tax assets, valuation allowance	17,524,000	21,676,000		17,524,000
Deferred tax assets, operating loss carryforwards, state and local	300,000			300,000
Tax credit carryforwards	4,100,000			4,100,000
Significant change in unrecognized tax benefits is reasonably possible, amount of unrecorded benefit	8,300,000			8,300,000
Unrecognized tax benefits that would impact effective tax rate	47,300,000			47,300,000
Penalty expense	500,000	800,000	1,100,000
Interest (income) expense	(100,000)	(100,000)	$ 400,000
Liability for penalties	11,700,000	4,700,000		11,700,000
Liability for interest	6,600,000	$ 4,000,000		6,600,000
Subject To Expiration
Income Tax Contingency [Line Items]
Tax credit carryforwards	3,500,000			3,500,000
Subject To Utilization Limitations
Income Tax Contingency [Line Items]
Tax credit carryforwards	1,200,000			1,200,000
Not Subject To Expiration
Income Tax Contingency [Line Items]
Tax credit carryforwards	600,000			600,000
Foreign Country
Income Tax Contingency [Line Items]
Net operating loss carryforwards	142,000,000			142,000,000
Federal Domestic
Income Tax Contingency [Line Items]
Net operating loss carryforwards	4,200,000			4,200,000
Operating Loss Carryforward With No Expiration Date | Foreign Country
Income Tax Contingency [Line Items]
Net operating loss carryforwards	113,200,000			113,200,000
Subject To Expiration | Foreign Country
Income Tax Contingency [Line Items]
Net operating loss carryforwards	$ 28,800,000			$ 28,800,000
Maximum
Income Tax Contingency [Line Items]
Effective income tax rate reconciliation, deduction, percent	50.00%

Income Taxes (Components Of Inc

Income Taxes (Components Of Income Before Income Taxes) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Domestic	$ 448,271	$ 455,478	$ 344,447
Foreign	74,312	31,607	51,247
Income before income tax provision	$ 522,583	$ 487,085	$ 395,694

Income Taxes (Components Of Pro

Income Taxes (Components Of Provision For Income Taxes) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Current, Federal	$ 44,824	$ 58,138	$ 112,414
Current, State	9,554	12,888	7,879
Current, Foreign	31,421	30,359	18,843
Deferred, Federal	(8,833)	(20,764)	(7,387)
Deferred, State	(965)	(2,901)	(584)
Deferred, Foreign	(4,713)	(10,010)	5,278
Total	$ 71,288	$ 67,710	$ 136,443

Income Taxes (Reconciliation Of

Income Taxes (Reconciliation Of U.S. Federal Statutory Tax Rate To Consolidated Effective Tax Rate) (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Federal statutory tax rate	21.00%	21.00%	35.00%
State income taxes, net of federal benefit	1.50%	1.50%	1.10%
Foreign rate differential	0.80%	0.80%	0.10%
Uncertain tax positions	(0.20%)	0.50%	0.30%
U.S. tax reform enactment	(0.40%)	0.20%	4.50%
Effective income tax rate reconciliation, change in deferred tax assets valuation allowance, percent	(1.30%)	0.00%	0.00%
Domestic production activity benefit	0.00%	0.00%	(2.60%)
Benefit from entity restructuring	0.00%	(1.40%)	0.00%
Research and development credits	(2.20%)	(2.30%)	(1.40%)
Stock-based compensation	(3.10%)	(3.30%)	(3.10%)
Foreign-derived intangible income deduction	(3.80%)	(3.90%)	0.00%
Other	1.30%	0.80%	0.60%
Consolidated effective tax rate	13.60%	13.90%	34.50%

Income Taxes (Components Of Def

Income Taxes (Components Of Deferred Tax Assets And Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Net operating loss carryforwards	$ 35,044	$ 39,290
Operating lease liabilities	26,628	0
Stock-based compensation	24,254	20,464
Uncertain tax positions	19,227	17,823
Employee benefits	9,392	15,048
Research and development credits	5,865	5,951
Other	6,309	4,121
Valuation allowance	(17,524)	(21,676)
Deferred tax assets	109,195	81,021
Other intangible assets	(99,193)	(38,787)
Operating lease right-of-use assets	(25,648)	0
Accounting method change	(21,396)	(31,626)
Deferred revenue	(13,744)	(12,021)
Property and equipment	(3,780)	(2,034)
Deferred tax liabilities	(163,761)	(84,468)
Net deferred tax liabilities	$ (54,566)	$ (3,447)

Income Taxes (Reconciliation _2

Income Taxes (Reconciliation Of Unrecognized Tax Benefits) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefit as of January 1	$ 22,827	$ 19,657	$ 15,209
Gross increases-acquisitions	26,914	0	0
Gross increases-tax positions in prior period	207	1,229	905
Gross decreases-tax positions in prior period	(1,743)	(376)	(765)
Gross increases-tax positions in current period	3,563	4,014	3,757
Reductions due to a lapse of the applicable statute of limitations	(2,230)	(994)	(847)
Changes due to currency fluctuation	(453)	(703)
Changes due to currency fluctuation			1,414
Settlements	0	0	(16)
Unrecognized tax benefit as of December 31	$ 49,085	$ 22,827	$ 19,657

Pension And Profit-Sharing Pl_2

Pension And Profit-Sharing Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Contribution Plan Disclosure [Line Items]
Total unfunded portion of the defined benefit obligations	$ 11.2
Expenses related to retirement programs	$ 16.3	$ 12.4	$ 10.1
Four Zero One K Plan
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 | Four Zero One K Plan
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 | Four Zero One K Plan
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 - Addi

Stock-Based Compensation - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Shares authorized for grant under the plan	39,800,000
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%
Maximum months after sale event where awards fully vest when service relationship terminated without cause	18 months
Minimum number of days that may be granted to terminated employee to exercise awards prior to termination	15 days
Restricted stock granted	843,000	681,000	866,000
Stock-based compensation expense	$ 116,190,000	$ 83,346,000	$ 53,154,000
Employee Stock Option
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Total unrecognized estimated unvested stock option compensation cost	$ 1,000,000
Weighted-average period of recognition of unrecognized compensation cost (years)	1 year
Performance Shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Restricted stock unit vesting period	3 years
RSU grant date fair value	$ 238.99	$ 191.76	$ 120.94
Restricted Stock
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Stock-based compensation expense	$ 109,900,000	$ 77,400,000	$ 46,300,000
Director Restricted Stock Units
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Restricted stock granted	11,259	13,632	18,018
RSU grant date fair value	$ 187.53	$ 165.71	$ 123.38
Stock-based compensation expense	$ 2,500,000	$ 2,300,000	$ 2,600,000
Market and Service Condition Stock Units
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Restricted stock unit vesting period	3 years
Minimum | Restricted Stock Units (RSUs)
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Restricted stock unit vesting period	3 years
Maximum
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Expiration period of options from the date of grant	10 years
Expiration period for optionee who meets the 10% criteria	5 years
Maximum | Restricted Stock Units (RSUs)
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Restricted stock unit vesting period	4 years
ANSYS 1996 Employee Stock Purchase Plan | Employee Stock
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Shares authorized for grant under the plan	1,800,000
Expiration period of options from the date of grant	6 months
Share-based compensation arrangement by share-based payment award, maximum employee subscription rate	10.00%
Share-based compensation arrangement by share-based payment award, maximum number of shares per employee	3,840
Share-based compensation arrangement by share-based payment award, purchase price of common stock, percent	90.00%
Share-based compensation arrangement by share-based payment award, maximum dollar amount of common stock purchasable in a calendar year	$ 25,000
Share-based compensation arrangement by share-based payment award, shares issued as of date	1,600,000
Stock-based compensation expense	$ 2,000,000	$ 1,800,000	$ 1,200,000
ANSYS 1996 Employee Stock Purchase Plan | Maximum | Employee Stock
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, eligibility, ownership percentage	5.00%

Stock-Based Compensation (Stock

Stock-Based Compensation (Stock-Based Compensation Expense) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense before taxes	$ 116,190	$ 83,346	$ 53,154
Related income tax benefits	(47,454)	(34,518)	(20,503)
Stock-based compensation expense, net of taxes	$ 68,736	$ 48,828	$ 32,651
Basic earnings per share	$ (0.82)	$ (0.58)	$ (0.38)
Diluted earnings per share	$ (0.80)	$ (0.57)	$ (0.38)
Software Licenses
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense before taxes	$ 0	$ 0	$ 969
Maintenance and service
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense before taxes	8,494	5,224	2,533
Selling, General And Administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense before taxes	60,639	47,099	30,817
Research And Development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense before taxes	$ 47,057	$ 31,023	$ 18,835

Stock-Based Compensation (Summa

Stock-Based Compensation (Summary Of Stock Options) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
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	$ 62.80	$ 59.17	$ 56.37
Granted, Weighted-Average Exercise Price	0	0	0
Exercised, Weighted-Average Exercise Price	53.53	50.92	49.78
Forfeited, Weighted-Average Exercise Price	64.21	86.28	80.92
Outstanding, end of year, Weighted-Average Exercise Price	67.49	62.80	59.17
Vested and Exercisable, end of year, Weighted-Average Exercise Price	65.71	59.69	55.11
Nonvested, Weighted-Average Exercise Price	$ 94.77	$ 93.44	$ 91.71
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding, beginning of year, Options	1,484	2,170	3,136
Granted, Options	0	0	0
Exercised, Options	(495)	(679)	(956)
Forfeited, Options	(5)	(7)	(10)
Outstanding, end of year, Options	984	1,484	2,170
Vested and Exercisable, end of year, Options	924	1,347	1,930
Nonvested, Options	60	137	240
Outstanding, Weighted-Average Remaining Contractual Term (in years)	3 years 2 months 4 days	3 years 6 months 18 days	4 years 1 month 6 days
Vested and Exercisable, Weighted-Average Remaining Contractual Term (in years)	2 years 11 months 12 days	3 years 1 month 20 days	3 years 6 months 25 days
Nonvested, Weighted-Average Remaining Contractual Term (in years)	6 years 8 months 15 days	7 years 7 months 6 days	8 years 3 months 18 days
Exercised, Aggregate Intrinsic Value	$ 72,098	$ 78,648	$ 58,472
Outstanding, Aggregate Intrinsic Value	186,926	118,908	191,895
Vested and Exercisable, Aggregate Intrinsic Value	177,111	112,133	178,456
Nonvested, Aggregate Intrinsic Value	9,815	6,775	13,439
Compensation Expense - Stock Options (in thousands)	$ 1,709	$ 2,006	$ 2,948

Stock-Based Compensation (Infor

Stock-Based Compensation (Information Regarding Stock Options Outstanding) (Details) shares in Thousands	12 Months Ended
	Dec. 31, 2019$ / sharesshares
$11.99 - $48.97
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Range of Exercise Prices, Lower Limit	$ 11.99
Range of Exercise Prices, Upper Limit	$ 48.97
Options Outstanding, Options | shares	181
Options Outstanding, Weighted-Average Remaining Contractual Life (years)	1 year 3 days
Options Outstanding, Weighted-Average Exercise Price	$ 43.29
Options Exercisable, Options | shares	181
Options Exercisable, Weighted-Average Remaining Contractual Life (years)	1 year 3 days
Options Exercisable, Weighted-Average Exercise Price	$ 43.29
Options Unvested, Options | shares	0
Options Unvested, Weighted-Average Remaining Contractual Life (years)	0 years
Options Unvested, Weighted-Average Exercise Price	$ 0
$58.67
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Range of Exercise Prices, Lower Limit	58.67
Range of Exercise Prices, Upper Limit	$ 58.67
Options Outstanding, Options | shares	267
Options Outstanding, Weighted-Average Remaining Contractual Life (years)	1 year 10 months 13 days
Options Outstanding, Weighted-Average Exercise Price	$ 58.67
Options Exercisable, Options | shares	267
Options Exercisable, Weighted-Average Remaining Contractual Life (years)	1 year 10 months 13 days
Options Exercisable, Weighted-Average Exercise Price	$ 58.67
Options Unvested, Options | shares	0
Options Unvested, Weighted-Average Remaining Contractual Life (years)	0 years
Options Unvested, Weighted-Average Exercise Price	$ 0
$67.44
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Range of Exercise Prices, Lower Limit	67.44
Range of Exercise Prices, Upper Limit	$ 67.44
Options Outstanding, Options | shares	280
Options Outstanding, Weighted-Average Remaining Contractual Life (years)	2 years 10 months 13 days
Options Outstanding, Weighted-Average Exercise Price	$ 67.44
Options Exercisable, Options | shares	280
Options Exercisable, Weighted-Average Remaining Contractual Life (years)	2 years 10 months 13 days
Options Exercisable, Weighted-Average Exercise Price	$ 67.44
Options Unvested, Options | shares	0
Options Unvested, Weighted-Average Remaining Contractual Life (years)	0 years
Options Unvested, Weighted-Average Exercise Price	$ 0
$76.31 - $95.09
Share-based Payment Arrangement, Option, Exercise Price Range [Line Items]
Range of Exercise Prices, Lower Limit	76.31
Range of Exercise Prices, Upper Limit	$ 95.09
Options Outstanding, Options | shares	256
Options Outstanding, Weighted-Average Remaining Contractual Life (years)	6 years 5 months 8 days
Options Outstanding, Weighted-Average Exercise Price	$ 93.89
Options Exercisable, Options | shares	196
Options Exercisable, Weighted-Average Remaining Contractual Life (years)	6 years 4 months 9 days
Options Exercisable, Weighted-Average Exercise Price	$ 93.62
Options Unvested, Options | shares	60
Options Unvested, Weighted-Average Remaining Contractual Life (years)	6 years 8 months 15 days
Options Unvested, Weighted-Average Exercise Price	$ 94.77

Stock-Based Compensation (Assum

Stock-Based Compensation (Assumptions To Estimate Fair Value Of Stock Awards) (Details) - Restricted Stock Unit Compensation Expense - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Risk-free interest rate	2.50%	2.40%	1.50%
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
Correlation factor	0.71	0.65	0.70
Weighted average fair value per share	$ 238.99	$ 191.76	$ 120.94
Ansys Stock Price
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Expected volatility	23.00%	21.00%	19.00%
Nasdaq Composite Index
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Expected volatility	16.00%	15.00%	15.00%

Stock-Based Compensation (Sum_2

Stock-Based Compensation (Summary of Restricted Stock Units) (Details) - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Nonvested, beginning of year, RSUs	1,522	1,361	906
Granted, RSUs	843	681	866
Performance adjustment, RSUs	74	76	35
Vested, RSUs	(704)	(524)	(341)
Forfeited, RSUs	(117)	(72)	(105)
Nonvested, end of year, RSUs	1,618	1,522	1,361
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Nonvested, beginning of year, Weighted-Average Grant Date Fair Value, RSUs	$ 129.96	$ 100.66	$ 86.45
Granted, Weighted-Average Grant Date Fair Value, RSUs	192.37	163.67	109.67
Performance adjustment, Weighted-Average Grant Date Fair Value, RSUs	167.87	151.52	98.29
Vested, Weighted-Average Grant Date Fair Value, RSUs	125.84	101.38	88.58
Forfeited, Weighted-Average Grant Date Fair Value, RSUs	140.43	125.29	90.80
Nonvested, end of year, Weighted-Average Grant Date Fair Value, RSUs	$ 165.26	$ 129.96	$ 100.66

Stock-Based Compensation (Sum_3

Stock-Based Compensation (Summary of Deferred Stock Awards to Non-Employee Directors) (Details) shares in Thousands	12 Months Ended
	Dec. 31, 2019shares
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Deferred awards outstanding, beginning of year	132,699
Shares diversified	0
Shares issued upon retirement	(67,020)
Deferred awards outstanding, end of year	65,679
Diversified Deferred Stock Award
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Deferred awards outstanding, beginning of year	12,250
Shares diversified	13,348
Shares issued upon retirement	(20,000)
Deferred awards outstanding, end of year	5,598
Undiversified Deferred Stock Award
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Deferred awards outstanding, beginning of year	120,449
Shares diversified	(13,348)
Shares issued upon retirement	(47,020)
Deferred awards outstanding, end of year	60,081

Stock Repurchase Program (Detai

Stock Repurchase Program (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Class of Stock Disclosures [Abstract]
Number of shares repurchased	330	1,674	2,750
Average price paid per share	$ 179.41	$ 161.12	$ 122.20
Total cost	$ 59,116	$ 269,801	$ 336,042

Stock Repurchase Program - Addi

Stock Repurchase Program - Additional Information (Details)	Dec. 31, 2019shares
Class of Stock Disclosures [Abstract]
Stock repurchase program, number of shares authorized to be repurchased	5,000,000
Stock repurchase program, remaining number of shares authorized to be repurchased	3,500,000

Royalty Agreements (Details)

Royalty Agreements (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cost of goods and services sold	$ 166,273,000	$ 155,885,000	$ 150,164,000
Royalty
Cost of goods and services sold	$ 22,400,000	$ 16,900,000	$ 16,000,000

Revenue by Geographic Area (Det

Revenue by Geographic Area (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 1,515,892	$ 1,293,636	$ 1,095,250
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	637,916	506,335	417,343
Japan
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	162,154	145,951	126,097
Germany
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	158,809	140,506	108,211
South Korea
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	90,082	72,724	63,011
France
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	68,551	67,657	53,672
China
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	64,725	57,567	54,415
Other EMEA
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	211,193	193,317	166,472
Other international
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 122,462	$ 109,579	$ 106,029

Property and Equipment by Geogr

Property and Equipment by Geographic Area (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property and equipment, net	$ 83,636	$ 61,655
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property and equipment, net	59,473	46,605
India
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property and equipment, net	5,660	4,176
Germany
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property and equipment, net	4,237	2,158
United Kingdom
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property and equipment, net	4,194	1,238
Other EMEA
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property and equipment, net	5,532	3,724
Other international
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property and equipment, net	$ 4,540	$ 3,754

Unconditional Purchase Obliga_3

Unconditional Purchase Obligations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Unconditional Purchase Obligations (Excluding Capital Stock Redemptions) [Abstract]
Unconditional purchase obligations, beginning of year	$ 24,200	$ 22,400	$ 14,100
Future expenditures under purchase obligations, next twelve months	37,183
Future expenditures under purchase obligations, year two	14,034
Future expenditures under purchase obligations, year three	10,689
Future expenditures under purchase obligations, year four	6,212
Future expenditures under purchase obligations, year five	3,264
Future expenditures under purchase obligations	$ 71,382

Restructuring (Details)

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

Contingencies and Commitments -

Contingencies and Commitments - Additional Information (Detail) $ in Millions	Dec. 31, 2019USD ($)
India Service Tax Audit
Loss Contingencies [Line Items]
Loss contingency, estimate of possible loss	$ 7.2

Schedule II - Valuation and Q_2

Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Provisions for doubtful accounts	$ 2,928	$ 1,577	$ 1,474
Allowance for Doubtful Accounts
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of year	8,000	6,800	5,700
Provisions for doubtful accounts	2,928	1,577	1,474
Deductions - returns and write-offs	2,228	377	374
Balance at end of year	$ 8,700	$ 8,000	$ 6,800

Uncategorized Items - anss20191

Label	Element	Value
Retained Earnings [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ 183,120,000