VeriSign (VRSN) 10-K 16 Feb 18 2017 FY Annual report Financial data

Document and Entity Information

Document and Entity Information Document - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2017	Feb. 09, 2018	Jun. 30, 2017
Document And Entity Information [Abstract]
Entity Registrant Name	VERISIGN INC/CA
Entity Central Index Key	1,014,473
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	Dec. 31, 2017
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Common Stock, Shares Outstanding		97,120,531
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 3.3

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 465,851	$ 231,945
Marketable securities	1,948,900	1,565,962
Other current assets	31,402	44,435
Total current assets	2,446,153	1,842,342
Property and equipment, net	263,513	266,125
Goodwill	52,527	52,527
Long-term deferred tax assets	15,392	9,385
Deposits Assets, Noncurrent	145,000	145,000
Other long-term assets	18,603	19,193
Total long-term assets	495,035	492,230
Total assets	2,941,188	2,334,572
Current liabilities:
Accounts payable and accrued liabilities	219,603	203,920
Deferred revenues	713,309	688,265
Convertible Debentures, including contingent interest derivative	627,616	629,764
Total current liabilities	1,560,528	1,521,949
Long-term deferred revenues	286,097	287,424
Senior Notes	1,782,529	1,237,189
Deferred Tax Liabilities, Net, Noncurrent	444,108	371,433
Other long-term tax liabilities	128,197	117,172
Total long-term liabilities	2,640,931	2,013,218
Total liabilities	4,201,459	3,535,167
Commitments and contingencies
Stockholders' deficit:
Preferred stock	0	0
Common stock	325	324
Additional paid-in capital	16,437,135	16,987,488
Accumulated deficit	(17,694,790)	(18,184,954)
Accumulated other comprehensive loss	(2,941)	(3,453)
Total stockholders' deficit	(1,260,271)	(1,200,595)
Total liabilities and stockholders' deficit	$ 2,941,188	$ 2,334,572

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares shares in Thousands	Dec. 31, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, authorized shares	5,000	5,000
Preferred stock, issued shares	0	0
Preferred stock, outstanding shares	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, authorized shares	1,000,000	1,000,000
Common Stock, Shares, Issued	325,218	324,118
Common stock, outstanding shares	97,591	103,091

Consolidated Statements Of Comp

Consolidated Statements Of Comprehensive Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement [Abstract]
Revenues	$ 1,165,095	$ 1,142,167	$ 1,059,366
Costs and expenses:
Cost of revenues	193,326	198,242	192,788
Sales and marketing	81,951	80,250	90,184
Research and development	52,342	59,100	63,718
General and administrative	129,754	118,003	106,730
Total costs and expenses	457,373	455,595	453,420
Operating income	707,722	686,572	605,946
Interest expense	(136,336)	(115,564)	(107,631)
Non-operating income, net	27,626	10,165	(10,665)
Income from continuing operations before income taxes	599,012	581,173	487,650
Income tax (expense) benefit	(141,764)	(140,528)	(112,414)
Net income	457,248	440,645	375,236
Realized foreign currency translation adjustments, included in net income	530	85	(291)
Change in unrealized gain on investments, net of tax	385	533	(519)
Realized gain on investments, net of tax, included in net income	(403)	(78)	(185)
Other comprehensive income (loss)	512	540	(995)
Comprehensive income	$ 457,760	$ 441,185	$ 374,241
Earnings per share
Earnings Per Share, Basic	$ 4.56	$ 4.12	$ 3.29
Earnings Per Share, Diluted	$ 3.68	$ 3.42	$ 2.82
Shares used to compute net income per share
Basic	100,325	107,001	114,155
Diluted	124,180	128,833	133,031

Consolidated Statements Of Stoc

Consolidated Statements Of Stockholders' Equity (Deficit) And Comprehensive Income (Loss) - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Total [Member]
Balance at Dec. 31, 2014		$ 322	$ 18,120,045	$ (19,000,835)	$ (2,998)	$ (883,466)
Balance, shares at Dec. 31, 2014		118,452
Net income	$ 375,236			375,236		375,236
Other Comprehensive Income (Loss), Net of Tax	(995)				(995)	(995)
Issuance of common stock under stock plans		$ 1	14,689			14,690
Issuance of common stock under stock plans, shares		1,291
Stock-based compensation			48,793			48,793
Net excess income tax benefits associated with stock-based compensation and other			18,464			18,464
Repurchase of common stock			(643,169)			(643,169)
Repurchase of common stock, shares		(9,671)
Balance at Dec. 31, 2015		$ 323	17,558,822	(18,625,599)	(3,993)	(1,070,447)
Balance, shares at Dec. 31, 2015		110,072
Net income	440,645			440,645		440,645
Other Comprehensive Income (Loss), Net of Tax	540				540	540
Issuance of common stock under stock plans		$ 1	13,669			13,670
Issuance of common stock under stock plans, shares		1,128
Stock-based compensation			52,430			52,430
Net excess income tax benefits associated with stock-based compensation and other			25,058			25,058
Repurchase of common stock			(662,491)			(662,491)
Repurchase of common stock, shares		(8,109)
Balance at Dec. 31, 2016	$ (1,200,595)	$ 324	16,987,488	(18,184,954)	(3,453)	(1,200,595)
Balance, shares at Dec. 31, 2016	103,091	103,091
Net income	$ 457,248			457,248		457,248
Other Comprehensive Income (Loss), Net of Tax	512				512	512
Issuance of common stock under stock plans		$ 1	12,914			12,915
Issuance of common stock under stock plans, shares		1,100
Stock-based compensation			55,362			55,362
Repurchase of common stock			(621,173)			(621,173)
Repurchase of common stock, shares		(6,600)
Balance at Dec. 31, 2017	$ (1,260,271)	$ 325	$ 16,437,135	$ (17,694,790)	$ (2,941)	$ (1,260,271)
Balance, shares at Dec. 31, 2017	97,591	97,591

Consolidated Statements Of Cash

Consolidated Statements Of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flows from operating activities:
Net income	$ 457,248,000	$ 440,645,000	$ 375,236,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation of property and equipment and amortization of other intangible assets	49,878,000	58,167,000	61,491,000
Stock-based compensation	52,907,000	50,044,000	46,075,000
Gain (Loss) on Disposition of Business	(10,421,000)	0	0
Unrealized Gain (Loss) on Derivatives	893,000	(2,402,000)	14,130,000
contingent interest payment for debenture	(15,232,000)	(13,385,000)	(10,759,000)
Amortization of Financing Costs and Discounts	14,678,000	13,411,000	12,292,000
Investment Income, Amortization of Discount	(14,860,000)	(5,527,000)	(1,843,000)
Other Operating Activities, Cash Flow Statement	(67,000)	1,740,000	62,000
Changes in operating assets and liabilities
Prepaid expenses and other assets	(13,775,000)	(8,109,000)	1,067,000
Accounts payable and accrued liabilities	15,483,000	40,244,000	21,013,000
Deferred revenues	25,348,000	14,347,000	70,988,000
Net deferred income taxes and other long term tax liabilities	113,131,000	87,614,000	82,328,000
Net Cash Provided by (Used in) Operating Activities	702,761,000	693,007,000	669,946,000
Cash flows from investing activities:
Proceeds from maturities and sales of marketable securities	4,562,161,000	3,817,899,000	2,767,027,000
Purchases of marketable securities	(4,929,834,000)	(3,691,057,000)	(3,219,329,000)
Purchases of property and equipment	(49,499,000)	(26,574,000)	(40,656,000)
Payments to Acquire Intangible Assets	0	(143,000,000)	0
Other investing activities	12,096,000	2,333,000	(3,941,000)
Net cash provided by (used in) investing activities	(405,076,000)	(40,399,000)	(496,899,000)
Cash flows from financing activities:
Proceeds from issuance of common stock from option exercises and employee stock purchase plans	12,915,000	13,670,000	14,690,000
Repurchases of common stock	(621,173,000)	(662,491,000)	(643,169,000)
Proceeds received from borrowing	543,185,000	0	492,237,000
Net cash used in financing activities	(65,073,000)	(648,821,000)	(136,242,000)
Effect of exchange rate changes on cash and cash equivalents	1,294,000	(501,000)	246,000
Net increase (decrease) in cash and cash equivalents	233,906,000	3,286,000	37,051,000
Cash and cash equivalents at beginning of period	231,945,000	228,659,000	191,608,000
Cash and cash equivalents at end of period	465,851,000	231,945,000	228,659,000
Supplemental cash flow disclosures:
Cash paid for interest, net of capitalized interest	117,234	115,544	99,473
Cash paid for income taxes, net of refunds received	$ 28,294,000	$ 14,303,000	$ 39,723,000

Description Of Business And Sum

Description Of Business And Summary Of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2017
Description Of Business And Summary Of Significant Accounting Policies [Abstract]
Description of Business and Summary of Significant Accounting Policies	Description of Business and Summary of Significant Accounting Policies Description of Business VeriSign, Inc. (“Verisign” or “the Company”) was incorporated in Delaware on April 12, 1995. The Company has one reportable segment, which consists of Registry Services and Security Services. Registry Services ensure the security, stability and resiliency of key internet infrastructure and services, including the . com and . net domains, two of the Internet’s root servers, and operation of the root-zone maintainer functions for the core of the internet’s Domain Name System (“DNS”). Security Services provides infrastructure assurance services consisting of Distributed Denial of Services (“DDoS”) Protection Services, and Managed DNS Services. On April 1, 2017, the Company completed the sale of its iDefense business. Basis of Presentation The accompanying consolidated financial statements of Verisign and its subsidiaries have been prepared in conformity with generally accepted accounting principles (“GAAP”) in the United States (“U.S.”). All significant intercompany accounts and transactions have been eliminated. The preparation of these consolidated financial statements requires management to make estimates and judgments that affect the reported amounts of assets, liabilities, revenues and expenses, and related disclosures of contingent assets and liabilities. Actual results may differ from these estimates under different assumptions or conditions. Reclassifications Certain reclassifications have been made to prior period amounts to conform to current period presentation. Such reclassifications have no effect on net income as previously reported. Adoption of New Accounting Standards Effective January 1, 2017, the Company adopted Accounting Standards Update (“ASU”) No. 2016-09, Improvements to Employee Share-Based Payment Accounting, issued by the Financial Accounting Standards Board (“FASB”). The new guidance requires excess tax benefits and tax deficiencies to be recorded as a discrete adjustment to income tax expense when stock awards vest, rather than in additional paid-in capital when they reduce income taxes payable. The Company also made the accounting policy election, as allowed by the new guidance, to account for forfeitures of stock awards as they occur, rather than estimating forfeitures. These changes were required to be applied on a modified retrospective basis through a cumulative-effect adjustment to the opening balance of retained earnings. The cumulative effect of adopting ASU 2016-09 was an increase in Deferred tax assets of $ 11.0 million , a decrease in Deferred tax liabilities of $ 24.4 million , an increase in Additional paid-in capital of $ 2.5 million , and a decrease in Accumulated deficit of $ 32.9 million , as of January 1, 2017, as a result of recognizing $ 35.4 million of previously unrecognized excess tax benefits from stock-based compensation, and a $ 2.5 million adjustment related to the change in accounting policy for forfeitures. Additionally, the new guidance requires cash flows related to excess tax benefits from stock-based compensation to be recognized with other income tax cash flows in operating activities, rather than separately as a financing activity. The Company elected to apply this new cash flow presentation requirement retrospectively, which resulted in an increase to both net cash from operating activities and net cash used in financing activities of $ 25.1 million and $ 18.5 million for the years ended December 31, 2016 and 2015, respectively. Effective January 1, 2017, the Company adopted ASU 2017-04, Simplifying the Test for Goodwill Impairment , which was issued by the FASB. The guidance in the ASU simplifies certain aspects of the goodwill impairment test, including the elimination of the requirement to perform a qualitative assessment of the likelihood of a goodwill impairment for reporting units with a negative carrying value. All of the Company’s goodwill is included in the Registry Services reporting unit which has a negative carrying value. As a result, the Company will no longer be required to perform the qualitative assessment. Recent Accounting Pronouncements On May 28, 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers , which requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. The ASU will replace most existing revenue recognition guidance in U.S. GAAP when it becomes effective. The new standard will be effective for the Company’s 2018 fiscal year. The FASB also issued several amendments to the standard, including clarification on accounting for licenses of intellectual property and identifying performance obligations. Upon adoption the Company will record an asset of $ 27.3 million related to fees paid to ICANN for registrations and renewals of domain names ending in . com. These costs have historically been recognized as expense in the period of the registration or renewal but the Company has determined that they represent costs incurred to obtain a contract under the new guidance and will be capitalized and amortized over the respective domain terms beginning in 2018. The standard will be adopted on a modified retrospective basis and recorded as a cumulative effect adjustment to Accumulated deficit on January 1, 2018. This adjustment will be reflected in the financial statements included in our Form 10-Q for the three months ended March 31, 2018. Apart from this adjustment and the inclusion of the additional required disclosures, the Company does not expect the adoption of the new revenue standard to impact its consolidated financial statements. In February 2016, the FASB issued ASU No. 2016-02, Leases. The guidance introduces a lessee model that requires most leases to be reported on the balance sheet. This ASU will become effective for the Company on January 1, 2019 and requires the modified retrospective transition method. Based on its current portfolio of leases, the Company does not expect the adoption of this standard to have a material impact on its consolidated financial statements. Significant Accounting Policies Cash and Cash Equivalents Verisign considers all highly-liquid investments purchased with original maturities of three months or less to be cash equivalents. Cash and cash equivalents include certain money market funds, debt securities and various deposit accounts. Verisign maintains its cash and cash equivalents with financial institutions that have investment grade ratings and, as part of its cash management process, performs periodic evaluations of the relative credit standing of these financial institutions. Marketable Securities Marketable securities primarily consist of debt securities issued by the U.S. Treasury. All marketable securities are classified as available-for-sale and are carried at fair value. Unrealized gains and losses, net of taxes, are reported as a component of Accumulated other comprehensive loss. The specific identification method is used to determine the cost basis of the marketable securities sold. The Company classifies its marketable securities as current based on their nature and availability for use in current operations. Property and Equipment Property and equipment are stated at cost less accumulated depreciation. Depreciation is calculated using the straight-line method over the estimated useful lives of the assets of 35 to 47 years for buildings, 10 years for building improvements and three to five years for computer equipment, software, office equipment, and furniture and fixtures. Leasehold improvements are amortized using the straight-line method over the lesser of the estimated useful lives of the assets or associated lease terms. Capitalized Software Software included in property and equipment includes amounts paid for purchased software and development costs for internally developed software. The Company capitalized $ 17.7 million and $18.0 million of costs related to internally developed software during 2017 and 2016 , respectively. Goodwill and Other Long-lived Assets Goodwill represents the excess of purchase consideration over fair value of net assets of businesses acquired. Goodwill is not amortized, but instead tested for impairment. All of the Company’s goodwill is included in the Registry Services reporting unit which has a negative carrying value. Upon adoption of ASU 2017-04, Simplifying the Test for Goodwill Impairment in 2017, the Company is no longer required to perform the qualitative assessment at the end of each reporting period to determine if any events have occurred or circumstances exist that would indicate that it is more likely than not that a goodwill impairment exists. Long-lived assets, such as property, plant, and equipment are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset, or asset group, may not be recoverable. Such events or circumstances include, but are not limited to, a significant decrease in the fair value of the underlying business, a significant decrease in the benefits realized from an acquired business, difficulties or delays in integrating the business or a significant change in the operations of an acquired business. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset, or asset group, to estimated undiscounted future cash flows expected to be generated by the asset, or asset group. An impairment charge is recognized in the amount by which the carrying amount of the asset exceeds its fair value. As of December 31, 2017, the Company’s assets include a deposit related to the purchase of the contractual rights to the . web gTLD. The amount paid to date has been recorded as a deposit until such time that the contractual rights are transferred to the Company. This asset would be tested for recoverability if the Company were to determine that it is no longer probable that the rights will be transferred. At the time of the transfer of the contractual rights, the Company will record the amount as an indefinite-lived intangible asset subject to review for impairment on an annual basis or more frequently if events or changes in circumstances indicate that an impairment is more likely than not. 3.25% Junior Subordinated Convertible Debentures Due 2037 (“Subordinated Convertible Debentures”) Upon issuance of the Subordinated Convertible Debentures, Verisign separated the liability (debt) and equity (conversion option) components in a manner that reflected the borrowing rate for a similar non-convertible debt. The liability component was recognized based on the fair value of a similar instrument without a conversion feature at issuance. The excess of the principal amount of the Subordinated Convertible Debentures over the liability component at issuance is the equity component or debt discount. Such excess represents the estimated fair value of the conversion feature and is recorded as Additional paid-in capital. The debt discount is amortized using the Company’s effective interest rate over the term of the Subordinated Convertible Debentures as a non-cash charge to interest expense. The Subordinated Convertible Debentures also have a contingent interest payment provision that requires the Company to pay interest based on certain thresholds, and upon the occurrence of certain events, as outlined in the Indenture governing the Subordinated Convertible Debentures. The contingent interest payment provision was identified as an embedded derivative, and accounted for separately at fair value, with any gains and losses recorded in Non-operating income (loss), net. Contingent interest payments through August 15, 2017, reflected the settlement of the embedded derivative. Effective August 15, 2017, Verisign has the right to redeem the Subordinated Convertible Debentures under the terms of the indenture, Therefore, the fair value of the contingent interest embedded derivative for periods after August 15, 2017 is negligible and is no longer recognized separately. Expense for contingent interest payments after August 15, 2017 are included within Interest expense on the Consolidated Statements of Comprehensive Income. Foreign Currency Remeasurement Verisign conducts business in several different countries and transacts in multiple currencies. The functional currency for all of Verisign’s international subsidiaries is the U.S. Dollar. The Company’s subsidiaries’ financial statements are remeasured into U.S. Dollars using a combination of current and historical exchange rates and any remeasurement gains and losses are included in Non-operating income (loss), net. Remeasurement gains and losses were not significant in each of the last three years. Verisign maintains a foreign currency risk management program designed to mitigate foreign exchange risks associated with the monetary assets and liabilities that are denominated in currencies other than the U.S. dollar. The primary objective of this program is to minimize the gains and losses resulting from fluctuations in exchange rates. The Company does not enter into foreign currency transactions for trading or speculative purposes, nor does it hedge foreign currency exposures in a manner that entirely offsets the effects of changes in exchange rates. The program may entail the use of forward or option contracts, which are usually placed and adjusted monthly. These foreign currency forward contracts are derivatives and are recorded at fair market value. The Company records gains and losses on foreign currency forward contracts in Non-operating income (loss), net. Gains and losses related to foreign currency forward contracts were not significant in each of the last three years. As of December 31, 2017 , Verisign held foreign currency forward contracts in notional amounts totaling $29.7 million to mitigate the impact of exchange rate fluctuations associated with certain assets and liabilities held in foreign currencies. Revenue Recognition Verisign recognizes revenues when the following four criteria are met: • Persuasive evidence of an arrangement exists: It is the Company’s customary practice to have a written contract, signed by both the customer and Verisign or a service order form from those customers who have previously negotiated a standard master services agreement with Verisign. • Delivery has occurred or services have been rendered: The Company’s services are usually delivered continuously from service activation date through the term of the arrangement. • The fee is fixed or determinable: Substantially all of the Company’s revenue arrangements have fixed or determinable fees. • Collectability is reasonably assured: Collectability is assessed on a customer-by-customer basis. Verisign typically sells to customers for whom there is a history of successful collection. The majority of customers either maintain a deposit with Verisign or provide an irrevocable letter of credit in excess of the amounts owed. New customers are subjected to a credit review process that evaluates the customer’s financial condition and, ultimately, their ability to pay. If Verisign determines from the outset of an arrangement that collectability is not probable based upon its credit review process, revenues are recognized as cash is collected. Registry Services Registry Services revenues primarily arise from fixed fees charged to registrars for the initial registration or renewal of .com , .net , and other domain names. Revenues from the initial registration or renewal of domain names are deferred and recognized ratably over the registration term, generally one year and up to ten years. Fees for renewals and advance extensions to the existing term are deferred until the new incremental period commences. These fees are then recognized ratably over the renewal term. Verisign also offers promotional marketing programs to its registrars based upon market conditions and the business environment in which the registrars operate. Amounts payable to these registrars for such promotional marketing programs are usually recorded as a reduction of revenue. If Verisign obtains an identifiable benefit separate from the services it provides to the registrars, then amounts payable up to the fair value of the benefit received are recorded as advertising expenses and the excess, if any, is recorded as a reduction of revenue. Security Services Following the revenue recognition criteria above, revenues from Security Services are usually deferred and recognized over the service term, generally one to two years. Advertising Expenses Advertising costs are expensed as incurred and are included in Sales and marketing expenses. Advertising expenses, including costs for advertising campaigns conducted jointly with our registrar customers were $27.4 million , $17.2 million , and $16.0 million in 2017 , 2016 , and 2015 , respectively. Income Taxes Verisign uses the asset and liability method to account for income taxes. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and net operating loss carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The Tax Cuts and Jobs Act (“Tax Act”) was enacted on December 22, 2017, most provisions of which will take effect starting in 2018. The Tax Act makes substantial changes to U.S. taxation of corporations, including, lowering the U.S. federal corporate income tax rate from 35% to 21%, and instituting a territorial tax system, along with a one-time tax on accumulated foreign earnings. The effect on deferred tax assets and liabilities of a change in law or tax rates is recognized in income in the period that includes the enactment date. The Company records a valuation allowance to reduce deferred tax assets to an amount whose realization is more likely than not. For every tax-paying component and within each tax jurisdiction, all deferred tax liabilities and assets are offset and presented as a single net noncurrent asset or liability. The Company’s income taxes payable is reduced by the tax benefits from restricted stock unit (“RSU”) vestings equal to the fair market value of the stock at the vesting date. Subsequent to the adoption of ASU No. 2016-09, Improvements to Employee Share-Based Payment Accounting on January 1, 2017, if the income tax benefit at the exercise or vesting date differs from the income tax benefit recorded based on the grant date fair value of the RSUs, the excess or shortfall of the tax benefit is recognized within income tax expense. Among other changes, the Tax Act includes a provision designed to currently tax global intangible low-taxed income (“GILTI”). The Company is evaluating available accounting policy alternatives to either record the U.S. income tax effect of future GILTI inclusions in the period in which they arise or establish deferred taxes with respect to the expected future tax liabilities associated with future GILTI inclusions, but has not yet made a policy election. Verisign’s global operations involve dealing with uncertainties and judgments in the application of complex tax regulations in multiple jurisdictions. The final taxes payable are dependent upon many factors, including negotiations with taxing authorities in various jurisdictions and resolution of disputes arising from U.S. federal, state, and international tax audits. The Company may only recognize or continue to recognize tax positions that are more likely than not to be sustained upon examination. The Company adjusts these liabilities for uncertain tax positions in light of changing facts and circumstances; however, due to the complexity of some of these uncertainties, the ultimate resolution may result in a payment that is materially different from its current estimate of the tax liabilities. The Company’s assumptions, judgments and estimates relative to the value of a deferred tax asset take into account predictions of the amount and character of future taxable income, such as income from operations or capital gains income. Actual operating results and the underlying amount and character of income in future years could render the Company’s current assumptions, judgments and estimates of recoverable net deferred taxes inaccurate. Any of the assumptions, judgments and estimates mentioned above could cause the Company’s actual income tax obligations to differ from its estimates, thus materially impacting its financial condition and results of operations. Stock-based Compensation The Company’s stock-based compensation is primarily related to RSUs granted to employees and its employee stock purchase plan (“ESPP”). Stock-based compensation expense is typically recognized ratably over the requisite service period. Subsequent to the adoption of ASU No. 2016-09, Improvements to Employee Share-Based Payment Accounting on January 1, 2017, forfeitures of stock-based awards are no longer estimated at the time of grant but are recognized as they occur. The Company also grants RSUs which include performance conditions, and in some cases market conditions, to certain executives. The expense for these performance-based RSUs is recognized based on the probable outcome of the performance conditions. The expense recognized for awards with market conditions is based on the grant date fair value of the awards including the impact of the market conditions, using a Monte Carlo simulation model. The Company uses the Black-Scholes option pricing model to determine the fair value of its ESPP offerings. The determination of the fair value of stock-based payment awards using the Monte Carlo simulation model or the Black-Scholes option-pricing model is affected by the Company’s stock price as well as assumptions regarding a number of complex and subjective variables. Earnings per Share The Company computes basic earnings per share by dividing net income by the weighted-average number of common shares outstanding during the period. Diluted earnings per share gives effect to dilutive potential common shares, including outstanding stock options, unvested RSUs, ESPP offerings and the conversion spread related to the Subordinated Convertible Debentures using the treasury stock method. Fair Value of Financial Instruments The Company applies the following fair value hierarchy, which prioritizes the inputs used to measure fair value into three levels and bases the categorization within the hierarchy upon the lowest level of input that is available and significant to the fair value measurement: • Level 1: Observable inputs that reflect quoted prices (unadjusted) for identical assets or liabilities in active markets. • Level 2: Inputs reflect quoted prices for identical assets or liabilities in markets that are not active; quoted prices for similar assets or liabilities in active markets; inputs other than quoted prices that are observable for the assets or liabilities; or inputs that are derived principally from or corroborated by observable market data by correlation or other means. • Level 3: Unobservable inputs reflecting the Company’s own assumptions incorporated in valuation techniques used to determine fair value. These assumptions are required to be consistent with market participant assumptions that are reasonably available. The Company measures and reports certain financial assets and liabilities at fair value on a recurring basis, including its investments in money market funds classified as Cash and cash equivalents, marketable securities, and foreign currency forward contracts. Legal Proceedings Verisign is involved in various investigations, claims and lawsuits arising in the normal conduct of its business, none of which, in its opinion, will have a material adverse effect on its financial condition, results of operations, or cash flows. The Company cannot assure you that it will prevail in any litigation. Regardless of the outcome, any litigation may require the Company to incur significant litigation expense and may result in significant diversion of management attention. While certain legal proceedings and related indemnification obligations to which the Company is a party specify the amounts claimed, such claims may not represent reasonably possible losses. Given the inherent uncertainties of the litigation, the ultimate outcome of these matters cannot be predicted at this time, nor can the amount of possible loss or range of loss, if any, be reasonably estimated, except in circumstances where an aggregate litigation accrual has been recorded for probable and reasonably estimable loss contingencies. A determination of the amount of accrual required, if any, for these contingencies is made after careful analysis of each matter. The required accrual may change in the future due to new developments in each matter or changes in approach such as a change in settlement strategy in dealing with these matters. The Company does not believe that any such matter currently being reviewed will have a material adverse effect on its financial condition, results of operations, or cash flows.

Financial Instruments

Financial Instruments	12 Months Ended
	Dec. 31, 2017
Cash, Cash Equivalents And Marketable Securities [Abstract]
Cash, Cash Equivalents, and Marketable Securities [Text Block]	Financial Instruments Cash, Cash Equivalents, and Marketable Securities The following table summarizes the Company’s cash, cash equivalents, and marketable securities and the fair value categorization of the financial instruments measured at fair value on a recurring basis: As of December 31, 2017 2016 (In thousands) Cash $ 135,092 $ 39,183 Time deposits 3,682 4,632 Money market funds (Level 1) 116,068 134,790 Debt securities issued by the U.S. Treasury and other U.S. government corporations and agencies (Level 1) 2,169,172 1,626,764 Equity securities of public companies (Level 1) 25 2,174 Total $ 2,424,039 $ 1,807,543 Included in Cash and cash equivalents $ 465,851 $ 231,945 Included in Marketable securities 1,948,900 1,565,962 Included in Other assets (Restricted cash) 9,288 9,636 Total $ 2,424,039 $ 1,807,543 The fair value of the debt securities held as of December 31, 2017 was $2.2 billion , including less than $ 1.0 million of gross and net unrealized losses. All of the debt securities held as of December 31, 2017 have contractual maturities of less than one year. Fair Value Measurements The fair value of the Company’s investments in money market funds approximates their face value. Such instruments are classified as Level 1 and are included in Cash and cash equivalents. The fair value of the debt securities consisting of U.S. Treasury bills is based on their quoted market prices and are classified as Level 1. Debt securities purchased with original maturities in excess of three months are included in Marketable securities. Debt securities purchased with original maturities less than three months are included in Cash and cash equivalents. The fair value of the equity securities of public companies is based on quoted market prices and are classified as Level 1. Investments in equity securities of public companies are included in marketable securities. As of December 31, 2017 , the Company’s other financial instruments include cash, accounts receivable, restricted cash, and accounts payable whose carrying values approximated their fair values. The fair value of the Company’s Subordinated Convertible Debentures was $4.2 billion as of December 31, 2017 . The fair values of the Company’s senior notes due 2023 (the “2023 Senior Notes”), the senior notes due 2025 (the “2025 Senior Notes”), and the senior notes due 2027 (the “2027 Senior Notes”) were $772.9 million , $544.4 million , and $563.7 million , respectively, as of December 31, 2017 . The fair values of these debt instruments are based on available market information from public data sources and are classified as Level 2.

Other Balance Sheet Items

Other Balance Sheet Items	12 Months Ended
	Dec. 31, 2017
Balance Sheet Related Disclosures [Abstract]
Other Balance Sheet Items	Other Balance Sheet Items Other Current Assets Other current assets consist of the following: As of December 31, 2017 2016 (In thousands) Prepaid expenses $ 15,787 $ 14,385 Accounts receivable, net 5,111 13,051 Income taxes receivable 6,347 15,328 Other 4,157 1,671 Total other current assets $ 31,402 $ 44,435 Property and Equipment, Net The following table presents the detail of property and equipment, net: As of December 31, 2017 2016 (In thousands) Land $ 31,141 $ 31,141 Buildings and building improvements 246,654 246,237 Computer equipment and software 462,469 441,732 Capital work in progress 4,024 4,246 Office equipment and furniture 6,472 6,203 Leasehold improvements 1,403 1,350 Total cost 752,163 730,909 Less: accumulated depreciation (488,650 ) (464,784 ) Total property and equipment, net $ 263,513 $ 266,125 Goodwill The following table presents the detail of goodwill: As of December 31, 2017 2016 (In thousands) Goodwill, gross $ 1,537,843 $ 1,537,843 Accumulated goodwill impairment (1,485,316 ) (1,485,316 ) Total goodwill $ 52,527 $ 52,527 There was no impairment of goodwill or other long-lived assets recognized in any of the periods presented. Deposits to Acquire Intangible Assets As of December 31, 2017, the Company has recorded $145.0 million for the future assignment to the Company of contractual rights to the .web gTLD, pending resolution of objections by other applicants, regulatory review, and approval from ICANN. Upon assignment of the contractual rights, the Company will record the total investment as an indefinite-lived intangible asset. Other Long-Term Assets Other long-term assets consist of the following: As of December 31, 2017 2016 (In thousands) Long-term restricted cash 9,288 9,636 Other taxes receivable 5,673 5,673 Long-term prepaid expenses and other assets 3,642 3,884 Total other long-term assets $ 18,603 $ 19,193 Accounts Payable and Accrued Liabilities Accounts payable and accrued liabilities consist of the following: As of December 31, 2017 2016 (In thousands) Accounts payable $ 20,923 $ 19,455 Accrued employee compensation 51,481 61,426 Customer deposits, net 63,617 52,173 Interest Payable 47,357 27,701 Taxes payable and other tax liabilities 13,477 23,144 Other accrued liabilities 22,748 20,021 Total accounts payable and accrued liabilities $ 219,603 $ 203,920

Debt And Interest Expense

Debt And Interest Expense	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Debt And Interest Expense	Debt and Interest Expense Senior Notes As of December 31, 2017, the Company had senior notes outstanding of $1.8 billion , net of unamortized issuance costs. The balance of the senior notes includes the $ 550.0 million principal amount of 4.75% senior unsecured notes which were issued in July 2017. All of the outstanding senior notes were issued at par and are senior unsecured obligations of the Company. Interest is payable on each of the senior notes semi-annually. Each of the senior notes issuances is redeemable, in whole or in part, at the Company’s option at times and redemption prices specified in the indentures. The following table summarizes information related to our Senior notes (in thousands, except interest rates): As of December 31, 2017 2016 Issuance Date Maturity Date Interest Rate Principal Senior notes due 2023 April 16, 2013 May 1, 2023 4.625 % $ 750,000 $ 750,000 Senior notes due 2025 March 27, 2015 April 1, 2025 5.250 % 500,000 500,000 Senior notes due 2027 July 5, 2017 July 15, 2027 4.750 % 550,000 — Unamortized issuance costs (17,471 ) (12,811 ) Total senior notes $ 1,782,529 $ 1,237,189 The indenture governing the 2023 Senior Notes contains covenants that limit the ability of the Company and/or its restricted subsidiaries, under certain circumstances, to, among other things: (i) pay dividends or make distributions on, or redeem or repurchase, its capital stock; (ii) make certain investments; (iii) create liens on assets; (iv) enter into sale/leaseback transactions and (v) merge or consolidate or sell all or substantially all of its assets. These covenants are subject to a number of important limitations and exceptions. The Indenture also provides for events of default, which, if any of them occurs, may permit or, in certain circumstances, require the principal, premium, if any, accrued and unpaid interest and any other monetary obligations on all the then outstanding Notes to be due and payable immediately. The Company has remained in compliance with these covenants and no events of default have occurred over the term of the Notes. 2015 Credit Facility On March 31, 2015, the Company entered into a credit agreement for a $ 200.0 million committed senior unsecured revolving credit facility (the “2015 Credit Facility”). The 2015 Credit Facility includes financial covenants requiring that the Company’s interest coverage ratio not be less than 3.0 to 1.0 for any period of four consecutive quarters and the Company’s leverage ratio not exceed 2.5 to 1.0. As of December 31, 2017 , there were no borrowings outstanding under the facility and the Company was in compliance with the financial covenants. The 2015 Credit Facility expires on April 1, 2020 at which time any outstanding borrowings are due. Verisign may from time to time request lenders to agree on a discretionary basis to increase the commitment amount by up to an aggregate of $ 150.0 million. Subordinated Convertible Debentures In August 2007, Verisign issued $1.25 billion principal amount of 3.25% subordinated convertible debentures due August 15, 2037 , in a private offering. The Subordinated Convertible Debentures are initially convertible, subject to certain conditions, into shares of the Company’s common stock at a conversion rate of 29.0968 shares of common stock per $1,000 principal amount of Subordinated Convertible Debentures, representing an initial effective conversion price of approximately $34.37 per share of common stock. The Company’s common stock price exceeded the current conversion price threshold trigger of $ 44.68 during the fourth quarter of 2017 . Accordingly, the Subordinated Convertible Debentures were convertible at the option of each holder during the first quarter of 2018. Further, in the event of conversion, the Company intends, and has the ability, to settle the principal amount of the Subordinated Convertible Debentures in cash, and therefore, classified the debt component of the Subordinated Convertible Debentures, net of unamortized debt issuance costs as a current liability, as of December 31, 2017 . As of December 31, 2017 , the if-converted value of the Subordinated Convertible Debentures exceeded its principal amount. Based on the if-converted value of the Subordinated Convertible Debentures as of December 31, 2017 , the conversion spread could have required the Company to issue up to an additional 25.4 million shares of common stock. At issuance, the Company calculated the carrying value of the liability component as the present value of its cash flows using a discount rate of 8.5% (borrowing rate for similar non-convertible debt with no contingent payment options), adjusted for the fair value of the contingent interest feature, yielding an effective interest rate of 8.39% . The excess of the principal amount of the debt over the carrying value of the liability component is also referred to as the “debt discount” or “equity component” of the Subordinated Convertible Debentures. The debt discount has been amortized using the Company’s effective interest rate of 8.39% over the 30 year term of the Subordinated Convertible Debentures as a non-cash charge included in Interest expense. Interest is paid semiannually in arrears on August 15 and February 15. Proceeds upon issuance of the Subordinated Convertible Debentures were as follows (in thousands): Principal value of Subordinated Convertible Debentures $ 1,250,000 Less: Issuance costs (25,777 ) Net proceeds, Subordinated Convertible Debentures $ 1,224,223 Amounts recognized at issuance: Subordinated Convertible Debentures, including contingent interest derivative (net of issuance costs of $11,328) $ 546,915 Additional paid-in capital 418,996 Long-term deferred tax liabilities 267,225 Non-operating loss (8,913 ) Net proceeds, Subordinated Convertible Debentures $ 1,224,223 The table below presents the carrying amounts of the liability and equity components: As of December 31, 2017 2016 (In thousands) Debt discount upon issuance (net of issuance costs of $14,449) $ 686,221 $ 686,221 Deferred taxes associated with the debt discount upon issuance (267,225 ) (267,225 ) Carrying amount of equity component $ 418,996 $ 418,996 Principal amount of Subordinated Convertible Debentures $ 1,250,000 $ 1,250,000 Unamortized discount of liability component (612,303 ) (624,315 ) Unamortized debt issuance costs associated with the liability component (10,081 ) (10,260 ) Carrying amount of liability component 627,616 615,425 Contingent interest derivative — 14,339 Subordinated Convertible Debentures, including contingent interest derivative $ 627,616 $ 629,764 The Company evaluated its debt obligations, including the Subordinated Convertible Debentures subsequent to the enactment of the Tax Act which lowers the U.S. federal income tax rate and imposes a new limitation on interest deductibility for tax purposes. On February 15, 2018, the Company called for the redemption of all of the outstanding Subordinated Convertible Debentures. The debentures will be redeemed on May 1, 2018 at a redemption price equal to 100% of the principal, plus accrued but unpaid interest up to, but not including, the redemption date. The Subordinated Convertible Debentures called for redemption may be converted at any time before the close of business on Monday, April 30, 2018. If holders elect to convert their debentures, the Company intends to settle the $1.25 billion principal value in cash, and the excess value will be settled in shares of the Company’s stock. The following table presents the components of the Company’s interest expense: Year Ended December 31, 2017 2016 2015 (In thousands) Contractual interest on Subordinated Convertible Debentures $ 47,432 $ 40,625 $ 40,625 Contractual interest on Senior Notes 73,638 60,938 54,667 Amortization of debt discount on the Subordinated Convertible Debentures 12,012 11,094 10,218 Amortization of debt issuance costs and other interest expense 3,254 2,907 2,121 Total interest expense $ 136,336 $ 115,564 $ 107,631

Stockholders' Deficit

Stockholders' Deficit	12 Months Ended
	Dec. 31, 2017
Stockholders' Equity Note [Abstract]
Stockholders' Deficit	Stockholders’ Deficit Treasury Stock Treasury stock is accounted for under the cost method. Treasury stock includes shares repurchased under stock repurchase programs and shares withheld in lieu of minimum tax withholdings due upon vesting of RSUs. On February 9, 2017 , the Company’s Board of Directors (“Board”) authorized the repurchase of approximately $640.9 million of its common stock, in addition to the $359.1 million of its common stock remaining available for repurchase under the previous share repurchase program, for a total repurchase authorization of up to $1.0 billion of its common stock. The share repurchase program has no expiration date. Purchases made under the program could be effected through open market transactions, block purchases, accelerated share repurchase agreements or other negotiated transactions. As of December 31, 2017 there was approximately $ 477.4 million remaining available for repurchases under the share repurchase program. Effective February 8, 2018, the Company’s Board authorized the repurchase of approximately $585.8 million of its common stock, in addition to the $414.2 million of its common stock remaining available for repurchase under the previous share repurchase program, for a total repurchase authorization of up to $1.0 billion of its common stock. The summary of the Company’s common stock repurchases for 2017 , 2016 and 2015 are as follows: 2017 2016 2015 Shares Average Price Shares Average Price Shares Average Price (In thousands, except average price amounts) Total repurchases under the repurchase plans 6,265 $ 94.59 7,789 $ 81.73 9,338 $ 66.59 Total repurchases for tax withholdings 335 $ 85.27 320 $ 80.74 333 $ 64.03 Total repurchases 6,600 $ 94.12 8,109 $ 81.70 9,671 $ 66.50 Total costs $ 621,173 $ 662,491 $ 643,169 Since inception, the Company has repurchased 227.6 million shares of its common stock for an aggregate cost of $8.8 billion , which is recorded as a reduction of Additional paid-in capital. Accumulated Other Comprehensive Loss The following table summarizes the changes in the components of Accumulated other comprehensive loss for 2017 and 2016 : Foreign Currency Translation Adjustments Loss Unrealized (Loss) Gain On Investments Total Accumulated Other Comprehensive Loss (In thousands) Balance, December 31, 2015 $ (3,451 ) $ (542 ) $ (3,993 ) Changes 85 455 540 Balance, December 31, 2016 (3,366 ) (87 ) (3,453 ) Changes 530 (18 ) 512 Balance, December 31, 2017 $ (2,836 ) $ (105 ) $ (2,941 )

Calculation Of Net Income Per S

Calculation Of Net Income Per Share	12 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
Calculation Of Net Income Per Share Attributable To Verisign Stockholders	Calculation of Earnings per Share The following table presents the computation of weighted-average shares used in the calculation of basic and diluted earnings per share: Year Ended December 31, 2017 2016 2015 (In thousands) Weighted-average shares of common stock outstanding 100,325 107,001 114,155 Weighted-average potential shares of common stock outstanding: Conversion spread related to Subordinated Convertible Debentures 23,247 21,074 18,047 Unvested RSUs, and ESPP 608 758 829 Shares used to compute diluted earnings per share 124,180 128,833 133,031 The calculation of diluted weighted average shares outstanding, excludes potentially dilutive securities, the effect of which would have been anti-dilutive, as well as performance based RSUs granted by the Company for which the relevant performance criteria have not been achieved. The number of potential shares excluded from the calculation was not significant in any period presented.

Geographic And Customer Informa

Geographic And Customer Information	12 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Geographic And Customer Information	Geographic and Customer Information The Company generates revenue in the U.S.; Europe, the Middle East and Africa (“EMEA”); China; and certain other countries, including Canada, Australia and Japan. The following table presents a comparison of the Company’s geographic revenues: Year Ended December 31, 2017 2016 2015 (In thousands) U.S $ 694,759 $ 667,301 $ 639,170 EMEA 211,349 207,474 193,623 China 106,526 127,298 83,456 Other 152,461 140,094 143,117 Total revenues $ 1,165,095 $ 1,142,167 $ 1,059,366 Revenues for our Registry Services business are generally attributed to the country of domicile and the respective regions in which the Company’s registrars are located, however, this may differ from the regions where the registrars operate or where registrants are located. Revenue growth for each region may be impacted by registrars reincorporating, relocating, or from acquisitions or changes in affiliations of resellers. Revenue growth for each region may also be impacted by registrars domiciled in one region, registering domain names in another region. The following table presents a comparison of property and equipment, net of accumulated depreciation, by geographic region: As of December 31, 2017 2016 (In thousands) U.S. $ 258,231 $ 261,837 Other 5,282 4,288 Total property and equipment, net $ 263,513 $ 266,125 Major Customers One customer accounted for approximately 31% , 30% , and 31% of revenues in 2017 , 2016, and 2015 , respectively. The Company does not believe that the loss of this customer would have a material adverse effect on the Company’s business because, in that event, end-users of this customer would transfer to the Company’s other existing customers.

Employee Benefits And Stock-Bas

Employee Benefits And Stock-Based Compensation	12 Months Ended
	Dec. 31, 2017
Share-based Compensation [Abstract]
Employee Benefits And Stock-Based Compensation	Employee Benefits and Stock-based Compensation 401(k) Plan The Company maintains a defined contribution 401(k) plan (the “401(k) Plan”) for substantially all of its U.S. employees. Under the 401(k) Plan, eligible employees may contribute up to 50% of their pre-tax salary, subject to the Internal Revenue Service (“IRS”) annual contribution limits. The Company matches 50% of up to the first 6% of the employee’s annual salary contributed to the plan. The Company contributed $4.0 million in 2017 , $3.8 million in 2016 , and $3.7 million in 2015 under the 401(k) Plan. The Company can terminate matching contributions at its discretion at any time. Equity Incentive Plan The majority of Verisign’s stock-based compensation relates to RSUs. As of December 31, 2017 , a total of 10.5 million shares of common stock were reserved for issuance upon the vesting of RSUs and for the future grant of equity awards. On May 26, 2006, the stockholders of Verisign approved the 2006 Equity Incentive Plan, which was amended and restated on June 9, 2016 (the “2006 Plan”). The 2006 Plan authorizes the award of incentive stock options to employees and non-qualified stock options, restricted stock awards, RSUs, stock bonus awards, stock appreciation rights and performance shares to eligible employees, officers, directors, consultants, independent contractors and advisers. The 2006 Plan is administered by the Compensation Committee which may delegate to a committee of one or more members of the Board or Verisign’s officers the ability to grant certain awards and take certain other actions with respect to participants who are not executive officers or non-employee directors. RSUs are awards covering a specified number of shares of Verisign common stock that may be settled by issuance of those shares (which may be restricted shares). RSUs generally vest over four years. Certain performance-based RSUs, granted to the Company’s executives, vest over either three or four year terms. Additionally, the Company has granted fully vested RSUs to members of its Board in each of the last three years. The Compensation Committee may authorize grants with a different vesting schedule in the future. A total of 27.0 million common shares were authorized and reserved for issuance under the 2006 Plan. 2007 Employee Stock Purchase Plan On August 30, 2007, the Company’s stockholders approved the 2007 Employee Stock Purchase Plan, and in 2017 approved an amendment to increase the shares reserved for issuance by 2.5 million to a total of 8.5 million common shares authorized and reserved for issuance under the ESPP. Eligible employees may purchase common stock through payroll deductions by electing to have between 2% and 25% of their compensation withheld to cover the purchase price. Each participant is granted an option to purchase common stock on the first day of each 24-month offering period and this option is automatically exercised on the last day of each six-month purchase period during the offering period. The purchase price for the common stock under the ESPP is 85% of the lesser of the fair market value of the common stock on the first day of the applicable offering period or the last day of the applicable purchase period. Offering periods begin on the first business day of February and August of each year. As of December 31, 2017 , 3.5 million shares of the Company’s common stock remain reserved for future issuance under this plan. Stock-based Compensation Stock-based compensation is classified in the Consolidated Statements of Comprehensive Income in the same expense line items as cash compensation. The following table presents the classification of stock-based compensation: Year Ended December 31, 2017 2016 2015 (In thousands) Cost of revenues $ 7,030 $ 7,253 $ 7,009 Sales and marketing 5,688 5,738 6,763 Research and development 6,113 6,739 6,488 General and administrative 34,076 30,314 25,815 Total stock-based compensation $ 52,907 $ 50,044 $ 46,075 The following table presents the nature of the Company’s total stock-based compensation: Year Ended December 31, 2017 2016 2015 (In thousands) RSUs $ 38,087 $ 37,325 $ 36,664 Performance-based RSUs 13,270 11,512 8,078 ESPP 4,005 3,593 4,051 Capitalization (Included in Property and equipment, net) (2,455 ) (2,386 ) (2,718 ) Total stock-based compensation expenses $ 52,907 $ 50,044 $ 46,075 The income tax benefit that was included within Income tax expense related to these stock-based compensation expenses for 2017 , 2016 , and 2015 was $ 12.5 million, $ 17.7 million, and $ 16.0 million, respectively. In 2017, the tax benefit reflects the reduction in the U.S. statutory corporate tax rate from 35% to 21%. RSUs Information The following table summarizes unvested RSUs activity: Year Ended December 31, 2017 2016 2015 Shares Weighted-Average Grant-Date Fair Value Shares Weighted-Average Grant-Date Fair Value Shares Weighted-Average Grant-Date Fair Value (Shares in thousands) Unvested at beginning of period 1,846 $ 66.30 2,110 $ 54.77 2,179 $ 46.36 Granted 732 79.94 760 78.58 1,075 61.74 Vested and settled (885 ) 61.75 (873 ) 49.95 (932 ) 43.92 Forfeited (105 ) 72.90 (151 ) 61.57 (212 ) 51.47 1,588 $ 74.69 1,846 $ 66.30 2,110 $ 54.77 The RSUs in the table above include certain RSUs granted to the Company’s executives that are subject to performance conditions, and in some cases, market conditions. The unvested RSUs as of December 31, 2017 include approximately 0.4 million RSUs subject to performance and/or market conditions. The number of RSUs, subject to these performance and market conditions, that ultimately vest may range from zero to a maximum of 0.8 million RSUs depending on the level of performance achieved and whether any market conditions are satisfied. The closing price of Verisign’s stock was $ 114.44 on December 31, 2017 . As of December 31, 2017 , the aggregate market value of unvested RSUs was $ 181.7 million. The fair values of RSUs that vested during 2017 , 2016 , and 2015 were $ 75.9 million, $ 70.5 million, and $ 59.8 million, respectively. As of December 31, 2017 , total unrecognized compensation cost related to unvested RSUs was $ 77.5 million which is expected to be recognized over a weighted-average period of 2.5 years.

Non-operating income, net

Non-operating income, net	12 Months Ended
	Dec. 31, 2017
Non-operating (loss) income, net [Abstract]
Non-operating Income, Net	Non-operating Income (Loss), Net The following table presents the components of Non-operating income (loss), net: Year Ended December 31, 2017 2016 2015 (In thousands) Interest income $ 17,944 $ 6,191 $ 2,128 Gain on sale of business 10,421 — — Unrealized (loss) gain on contingent interest derivative on Subordinated Convertible Debentures (893 ) 2,402 (14,130 ) Other, net 154 1,572 1,337 Total non-operating income (loss), net $ 27,626 $ 10,165 $ (10,665 ) Interest income is earned principally from the Company’s surplus cash balances and marketable securities. On April 1, 2017, the Company completed the sale of its iDefense business, which resulted in a gain of approximately $10.4 million in 2017. The unrealized gains and losses on the contingent interest derivative on the Subordinated Convertible Debentures reflects the change in value of the derivative that results primarily from the changes in the Company’s stock price. The fair value of the contingent interest derivative for periods after August 15, 2017 is negligible due to the Company’s right to redeem the debentures. Contingent interest after August 15, 2017 was included in Interest expense.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2017
Income Taxes [Abstract]
Income Tax Disclosure [Text Block]	Income Taxes Income before income taxes is categorized geographically as follows: Year Ended December 31, 2017 2016 2015 (In thousands) United States $ 313,351 $ 299,304 $ 248,932 Foreign 285,661 281,869 238,718 Total income before income taxes $ 599,012 $ 581,173 $ 487,650 The provision for income taxes consisted of the following: Year Ended December 31, 2017 2016 2015 (In thousands) Current expense: Federal $ 16,870 $ 34,842 $ 13,601 State 294 240 156 Foreign, including withholding tax 15,539 19,268 17,241 32,703 54,350 30,998 Deferred expense (benefit): Federal 90,113 64,301 65,168 State 19,654 21,492 15,767 Foreign (706 ) 385 481 109,061 86,178 81,416 Total income tax expense $ 141,764 $ 140,528 $ 112,414 The difference between income tax expense and the amount resulting from applying the federal statutory rate of 35% to Income before income taxes is attributable to the following: Year Ended December 31, 2017 2016 2015 (In thousands) Income tax expense at federal statutory rate $ 209,654 $ 203,410 $ 170,677 State taxes, net of federal benefit 13,029 14,517 9,616 Differences between statutory rate and foreign effective tax rate (83,808 ) (79,087 ) (66,238 ) U.S. federal tax rate change (186,800 ) — — U.S. tax on accumulated foreign earnings, net of foreign tax credits 162,353 — — Foreign withholding tax on unremitted foreign earnings, net of foreign tax credits 33,619 — — Other (6,283 ) 1,688 (1,641 ) Total income tax expense $ 141,764 $ 140,528 $ 112,414 The Tax Act was enacted on December 22, 2017, most provisions of which will take effect starting in 2018. The Tax Act makes substantial changes to U.S. taxation of corporations, including, lowering the U.S. federal corporate income tax rate from 35% to 21% , and instituting a territorial tax system, along with a one-time tax on accumulated foreign earnings. Upon enactment, the Company remeasured its deferred tax balances to reflect the new 21% U.S. federal tax rate, which resulted in a tax benefit of $ 186.8 million in 2017. The Company also recorded a provisional deferred tax liability for the one-time U.S. tax of $ 162.4 million , triggered by the Tax Act, on accumulated foreign earnings, net of $ 38.3 million of resulting previously unrecognized foreign tax credits. As a result of the Tax Act, the Company no longer intends to indefinitely reinvest the earnings of its foreign subsidiaries offshore, and therefore, recognized a provisional deferred tax liability of $33.6 million for foreign withholding tax on its unremitted foreign earnings, net of $ 26.3 million of resulting foreign tax credits. The Company has not completed its accounting for the tax effects of the enactment of the Tax Act. Specifically, the amounts recorded for the U.S. tax on accumulated foreign earnings, net of foreign tax credits and the foreign withholding tax on unremitted foreign earnings, net of foreign tax credits, and the state income tax effects of these two items are provisional amounts based on the Company’s estimates. The Company expects to complete the accounting for these impacts of the Tax Act in the fourth quarter of 2018 as it finalizes its cumulative earnings and profits of its foreign subsidiaries and receives additional guidance from the IRS pertaining to the Tax Act. The impacts of additional guidance and changes in estimates related to the effects of the Tax Act, if any, will be recorded in the period the additional guidance or information is available. The Company qualifies for a tax holiday in Switzerland which does not expire, unless the required non-Swiss income and expense thresholds are no longer met, or there is a law change which eliminates the holiday. The tax holiday provides reduced rates of taxation on certain types of income and also require certain thresholds of foreign source income. The tax holiday increased the Company’s earnings per share by $0.10 , $ 0.16 , and $ 0.14 in 2017, 2016, and 2015, respectively. The tax effects of temporary differences that give rise to significant portions of the Company’s deferred tax assets and liabilities are as follows: As of December 31, 2017 2016 (In thousands) Deferred tax assets: Net operating loss carryforwards $ 70,587 $ 46,879 Deductible goodwill and intangible assets 1,192 10,473 Tax credit carryforwards 52,659 59,337 Deferred revenue, accruals and reserves 77,869 114,548 Capital loss carryforwards 778,430 1,161,772 Other 5,584 4,791 Total deferred tax assets 986,321 1,397,800 Valuation allowance (783,725 ) (1,162,101 ) Net deferred tax assets 202,596 235,699 Deferred tax liabilities: Property and equipment (1,577 ) (4,212 ) U.S. tax on accumulated foreign earnings (162,912 ) — Foreign withholding tax on unremitted earnings (33,619 ) — Subordinated Convertible debentures (430,088 ) (590,921 ) Other (3,116 ) (2,614 ) Total deferred tax liabilities (631,312 ) (597,747 ) Total net deferred tax liabilities $ (428,716 ) $ (362,048 ) With the exception of deferred tax assets related to capital loss and certain state net operating loss carryforwards, management believes it is more likely than not that the tax effects of the deferred tax liabilities together with future taxable income, will be sufficient to fully recover the remaining deferred tax assets. As of December 31, 2017 , the Company had federal, state and foreign net operating loss carryforwards of approximately $ 5.5 million , $1.3 billion and $ 18.9 million , respectively, before applying tax rates for the respective jurisdictions. As of December 31, 2017 , the Company had federal and state research tax credits of $ 4.2 million and $2.3 million , respectively, and alternative minimum tax credits of $ 17.0 million available for future years. Certain net operating loss carryforwards and credits are subject to an annual limitation under Internal Revenue Code Section 382, but are expected to be fully realized. The federal and state net operating loss and federal tax credit carryforwards expire in various years from 2018 through 2034 . The foreign net operating loss can be carried forward indefinitely. As of December 31, 2017 , the Company had federal and state capital loss carryforwards of $ 2.9 billion and $ 3.1 billion , respectively, before applying tax rates for the respective jurisdictions. The capital loss carryforwards expire in 2018 and are also subject to annual limitations under Internal Revenue Code Section 382. The Company does not expect to realize any tax benefits from the capital loss carryforwards and accordingly has reserved the entire amount through valuation allowance and accrual for uncertain tax positions. As of December 31, 2017, the Company has foreign tax credit carryforwards of $ 121.5 million . The majority of these foreign tax credits will expire in 2024 . The deferred tax liability related to the Subordinated Convertible Debentures is driven by the excess of the tax deduction taken for interest expense over the amount of interest expense recognized in the consolidated financial statements. The interest expense deducted for tax purposes is based on the adjusted issue price of the Subordinated Convertible Debentures, while the interest expense recognized in accordance with GAAP is based only on the liability portion of the Subordinated Convertible Debentures. The adjusted issue price of the Subordinated Convertible Debentures grows over the term due to the difference between the interest deduction taken for income tax, using a comparable yield of 8.5% , and the coupon rate of 3.25% , compounded annually, adjusted for actual versus projected contingent interest payments The Company maintains liabilities for uncertain tax positions. These liabilities involve considerable judgment and estimation and are continuously monitored by management based on the best information available including changes in tax regulations and other information. A reconciliation of the beginning and ending balances of the total amounts of gross unrecognized tax benefits is as follows: As of December 31, 2017 2016 (In thousands) Beginning balance $ 220,682 $ 220,280 Increases in tax positions for prior years 3,699 119 Decreases in tax positions for prior years (144 ) (71 ) Increases in tax positions for current year 395 354 Decreases in tax positions due to settlement with taxing authorities (1,416 ) — Ending balance $ 223,216 $ 220,682 As of December 31, 2017 , approximately $ 217.0 million of unrecognized tax benefits, including penalties and interest, could affect the Company’s tax provision and effective tax rate. It is reasonably possible that during the next twelve months, the Company’s unrecognized tax benefits may change by a significant amount as a result of IRS audits. However the timing of completion and ultimate outcome of the audits remains uncertain. Therefore, the Company cannot currently estimate the impact on the balance of unrecognized tax benefits. In accordance with its accounting policy, the Company recognizes accrued interest and penalties related to unrecognized tax benefits as a component of tax expense. These accruals were not material in any period presented. The Company’s major taxing jurisdictions are the U.S., the state of Virginia, and Switzerland. The Company’s U.S. federal income tax returns are currently under examination by the IRS for 2010 through 2014. The Company’s other tax returns are not currently under examination by their respective taxing jurisdictions. Because the Company has used net operating loss carryforwards and other tax attributes to offset its taxable income in current and future years’ income tax returns for the U.S. and Virginia, such attributes can be adjusted by these taxing authorities until the statute closes on the year in which such attributes were utilized. The open years in Switzerland are the 2012 tax year and forward.

Commitments And Contingencies

Commitments And Contingencies	12 Months Ended
	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments And Contingencies	Commitments and Contingencies Purchase Obligations and Contractual Agreements The following table represents the minimum payments required by Verisign under certain purchase obligations, leases, the .tv Agreement with the Government of Tuvalu, and the interest payments and principal on the Subordinated Convertible Debentures and the Senior Notes: Purchase Obligations .tv Agreement Senior Notes Subordinated Convertible Debentures Total (In thousands) 2018 $ 33,175 $ 5,000 $ 87,063 $ 1,279,388 $ 1,404,626 2019 4,893 5,000 87,063 — 96,956 2020 806 5,000 87,063 — 92,869 2021 612 5,000 87,063 — 92,675 2022 301 — 87,063 — 87,364 Thereafter — — 2,030,938 — 2,030,938 Total $ 39,787 $ 20,000 $ 2,466,253 $ 1,279,388 $ 3,805,428 The amounts included in the table above related to the Subordinated Convertible Debentures include the February 2018 coupon and contingent interest payments in addition to the repayment of the full principal amount as a result of the redemption of the debentures as discussed in Note 4, “Debt and Interest Expense.” The amounts in the table above exclude $ 217.0 million of income tax related uncertain tax positions, as the Company is unable to reasonably estimate the ultimate amount or time of settlement of those liabilities. Verisign enters into certain purchase obligations with various vendors. The Company’s significant purchase obligations include firm commitments with telecommunication carriers and other service providers. The Company does not have any significant purchase obligations beyond 2022. The Company has an agreement with Internet Corporation for Assigned Names and Numbers (“ICANN”) to be the sole registry operator for domain names in the .com registry through November 30, 2024 . Under this agreement, the Company pays ICANN on a quarterly basis, $ 0.25 for each annual increment of a domain name registered or renewed during such quarter. As of December 31, 2017 , there were 131.9 million domain names in the . com registry. However, the number of domain names registered and renewed each quarter may vary significantly. The Company incurred registry fees for the . com registry of $ 32.3 million in 2017 , $ 31.5 million in 2016 , and $ 30.9 million in 2015 . Registry fees for other top-level domains that we operate have been excluded from the table above because the amounts are variable or passed through to registrars. The Company has an agreement with the Government of Tuvalu to be the sole registry operator for .tv domain names through December 31, 2021. Registry fees were $ 5.0 million in each of the last three years. Verisign leases a small portion of its facilities under operating leases that extend into 2020. Rental expenses under operating leases were not material in any period presented. Future rental expenses under existing operating leases are not material. Off-Balance Sheet Arrangements As of December 31, 2017 and 2016 , the Company did not have any relationships with unconsolidated entities or financial partnerships, such as entities often referred to as structured finance or special purpose entities, which would have been established for the purpose of facilitating off-balance sheet arrangements or other contractually narrow or limited purposes. As such, the Company is not exposed to any financing, liquidity, market or credit risk that could arise if the Company had engaged in such relationships. It is not the Company’s business practice to enter into off-balance sheet arrangements. However, in the normal course of business, the Company does enter into contracts in which it makes representations and warranties that guarantee the performance of the Company’s products and services. Historically, there have been no significant losses related to such guarantees.

Description Of Business And S18

Description Of Business And Summary Of Significant Accounting Policies (Policy)	12 Months Ended
	Dec. 31, 2017
Description Of Business And Summary Of Significant Accounting Policies [Abstract]
Cash And Cash Equivalents	Cash and Cash Equivalents Verisign considers all highly-liquid investments purchased with original maturities of three months or less to be cash equivalents. Cash and cash equivalents include certain money market funds, debt securities and various deposit accounts. Verisign maintains its cash and cash equivalents with financial institutions that have investment grade ratings and, as part of its cash management process, performs periodic evaluations of the relative credit standing of these financial institutions.
Marketable Securities	Marketable Securities Marketable securities primarily consist of debt securities issued by the U.S. Treasury. All marketable securities are classified as available-for-sale and are carried at fair value. Unrealized gains and losses, net of taxes, are reported as a component of Accumulated other comprehensive loss. The specific identification method is used to determine the cost basis of the marketable securities sold. The Company classifies its marketable securities as current based on their nature and availability for use in current operations.
Property And Equipment	Property and Equipment Property and equipment are stated at cost less accumulated depreciation. Depreciation is calculated using the straight-line method over the estimated useful lives of the assets of 35 to 47 years for buildings, 10 years for building improvements and three to five years for computer equipment, software, office equipment, and furniture and fixtures. Leasehold improvements are amortized using the straight-line method over the lesser of the estimated useful lives of the assets or associated lease terms.
Capitalized Software	Capitalized Software Software included in property and equipment includes amounts paid for purchased software and development costs for internally developed software. The Company capitalized $ 17.7 million and $18.0 million of costs related to internally developed software during 2017 and 2016 , respectively.
Goodwill And Other Long-Lived Assets	Goodwill and Other Long-lived Assets Goodwill represents the excess of purchase consideration over fair value of net assets of businesses acquired. Goodwill is not amortized, but instead tested for impairment. All of the Company’s goodwill is included in the Registry Services reporting unit which has a negative carrying value. Upon adoption of ASU 2017-04, Simplifying the Test for Goodwill Impairment in 2017, the Company is no longer required to perform the qualitative assessment at the end of each reporting period to determine if any events have occurred or circumstances exist that would indicate that it is more likely than not that a goodwill impairment exists. Long-lived assets, such as property, plant, and equipment are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset, or asset group, may not be recoverable. Such events or circumstances include, but are not limited to, a significant decrease in the fair value of the underlying business, a significant decrease in the benefits realized from an acquired business, difficulties or delays in integrating the business or a significant change in the operations of an acquired business. Recoverability of assets to be held and used is measured by a comparison of the carrying amount of an asset, or asset group, to estimated undiscounted future cash flows expected to be generated by the asset, or asset group. An impairment charge is recognized in the amount by which the carrying amount of the asset exceeds its fair value. As of December 31, 2017, the Company’s assets include a deposit related to the purchase of the contractual rights to the . web gTLD. The amount paid to date has been recorded as a deposit until such time that the contractual rights are transferred to the Company. This asset would be tested for recoverability if the Company were to determine that it is no longer probable that the rights will be transferred. At the time of the transfer of the contractual rights, the Company will record the amount as an indefinite-lived intangible asset subject to review for impairment on an annual basis or more frequently if events or changes in circumstances indicate that an impairment is more likely than not.
3.25% Junior Subordinated Convertible Debentures Due 2037 ("Convertible Debentures")	3.25% Junior Subordinated Convertible Debentures Due 2037 (“Subordinated Convertible Debentures”) Upon issuance of the Subordinated Convertible Debentures, Verisign separated the liability (debt) and equity (conversion option) components in a manner that reflected the borrowing rate for a similar non-convertible debt. The liability component was recognized based on the fair value of a similar instrument without a conversion feature at issuance. The excess of the principal amount of the Subordinated Convertible Debentures over the liability component at issuance is the equity component or debt discount. Such excess represents the estimated fair value of the conversion feature and is recorded as Additional paid-in capital. The debt discount is amortized using the Company’s effective interest rate over the term of the Subordinated Convertible Debentures as a non-cash charge to interest expense. The Subordinated Convertible Debentures also have a contingent interest payment provision that requires the Company to pay interest based on certain thresholds, and upon the occurrence of certain events, as outlined in the Indenture governing the Subordinated Convertible Debentures. The contingent interest payment provision was identified as an embedded derivative, and accounted for separately at fair value, with any gains and losses recorded in Non-operating income (loss), net. Contingent interest payments through August 15, 2017, reflected the settlement of the embedded derivative. Effective August 15, 2017, Verisign has the right to redeem the Subordinated Convertible Debentures under the terms of the indenture, Therefore, the fair value of the contingent interest embedded derivative for periods after August 15, 2017 is negligible and is no longer recognized separately. Expense for contingent interest payments after August 15, 2017 are included within Interest expense on the Consolidated Statements of Comprehensive Income.
Foreign Currency Remeasurement	Foreign Currency Remeasurement Verisign conducts business in several different countries and transacts in multiple currencies. The functional currency for all of Verisign’s international subsidiaries is the U.S. Dollar. The Company’s subsidiaries’ financial statements are remeasured into U.S. Dollars using a combination of current and historical exchange rates and any remeasurement gains and losses are included in Non-operating income (loss), net. Remeasurement gains and losses were not significant in each of the last three years. Verisign maintains a foreign currency risk management program designed to mitigate foreign exchange risks associated with the monetary assets and liabilities that are denominated in currencies other than the U.S. dollar. The primary objective of this program is to minimize the gains and losses resulting from fluctuations in exchange rates. The Company does not enter into foreign currency transactions for trading or speculative purposes, nor does it hedge foreign currency exposures in a manner that entirely offsets the effects of changes in exchange rates. The program may entail the use of forward or option contracts, which are usually placed and adjusted monthly. These foreign currency forward contracts are derivatives and are recorded at fair market value. The Company records gains and losses on foreign currency forward contracts in Non-operating income (loss), net. Gains and losses related to foreign currency forward contracts were not significant in each of the last three years. As of December 31, 2017 , Verisign held foreign currency forward contracts in notional amounts totaling $29.7 million to mitigate the impact of exchange rate fluctuations associated with certain assets and liabilities held in foreign currencies.
Revenue Recognition	Revenue Recognition Verisign recognizes revenues when the following four criteria are met: • Persuasive evidence of an arrangement exists: It is the Company’s customary practice to have a written contract, signed by both the customer and Verisign or a service order form from those customers who have previously negotiated a standard master services agreement with Verisign. • Delivery has occurred or services have been rendered: The Company’s services are usually delivered continuously from service activation date through the term of the arrangement. • The fee is fixed or determinable: Substantially all of the Company’s revenue arrangements have fixed or determinable fees. • Collectability is reasonably assured: Collectability is assessed on a customer-by-customer basis. Verisign typically sells to customers for whom there is a history of successful collection. The majority of customers either maintain a deposit with Verisign or provide an irrevocable letter of credit in excess of the amounts owed. New customers are subjected to a credit review process that evaluates the customer’s financial condition and, ultimately, their ability to pay. If Verisign determines from the outset of an arrangement that collectability is not probable based upon its credit review process, revenues are recognized as cash is collected. Registry Services Registry Services revenues primarily arise from fixed fees charged to registrars for the initial registration or renewal of .com , .net , and other domain names. Revenues from the initial registration or renewal of domain names are deferred and recognized ratably over the registration term, generally one year and up to ten years. Fees for renewals and advance extensions to the existing term are deferred until the new incremental period commences. These fees are then recognized ratably over the renewal term. Verisign also offers promotional marketing programs to its registrars based upon market conditions and the business environment in which the registrars operate. Amounts payable to these registrars for such promotional marketing programs are usually recorded as a reduction of revenue. If Verisign obtains an identifiable benefit separate from the services it provides to the registrars, then amounts payable up to the fair value of the benefit received are recorded as advertising expenses and the excess, if any, is recorded as a reduction of revenue. Security Services Following the revenue recognition criteria above, revenues from Security Services are usually deferred and recognized over the service term, generally one to two years.
Advertising Expenses	Advertising Expenses Advertising costs are expensed as incurred and are included in Sales and marketing expenses. Advertising expenses, including costs for advertising campaigns conducted jointly with our registrar customers were $27.4 million , $17.2 million , and $16.0 million in 2017 , 2016 , and 2015 , respectively.
Income Taxes	Income Taxes Verisign uses the asset and liability method to account for income taxes. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and net operating loss carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The Tax Cuts and Jobs Act (“Tax Act”) was enacted on December 22, 2017, most provisions of which will take effect starting in 2018. The Tax Act makes substantial changes to U.S. taxation of corporations, including, lowering the U.S. federal corporate income tax rate from 35% to 21%, and instituting a territorial tax system, along with a one-time tax on accumulated foreign earnings. The effect on deferred tax assets and liabilities of a change in law or tax rates is recognized in income in the period that includes the enactment date. The Company records a valuation allowance to reduce deferred tax assets to an amount whose realization is more likely than not. For every tax-paying component and within each tax jurisdiction, all deferred tax liabilities and assets are offset and presented as a single net noncurrent asset or liability. The Company’s income taxes payable is reduced by the tax benefits from restricted stock unit (“RSU”) vestings equal to the fair market value of the stock at the vesting date. Subsequent to the adoption of ASU No. 2016-09, Improvements to Employee Share-Based Payment Accounting on January 1, 2017, if the income tax benefit at the exercise or vesting date differs from the income tax benefit recorded based on the grant date fair value of the RSUs, the excess or shortfall of the tax benefit is recognized within income tax expense. Among other changes, the Tax Act includes a provision designed to currently tax global intangible low-taxed income (“GILTI”). The Company is evaluating available accounting policy alternatives to either record the U.S. income tax effect of future GILTI inclusions in the period in which they arise or establish deferred taxes with respect to the expected future tax liabilities associated with future GILTI inclusions, but has not yet made a policy election. Verisign’s global operations involve dealing with uncertainties and judgments in the application of complex tax regulations in multiple jurisdictions. The final taxes payable are dependent upon many factors, including negotiations with taxing authorities in various jurisdictions and resolution of disputes arising from U.S. federal, state, and international tax audits. The Company may only recognize or continue to recognize tax positions that are more likely than not to be sustained upon examination. The Company adjusts these liabilities for uncertain tax positions in light of changing facts and circumstances; however, due to the complexity of some of these uncertainties, the ultimate resolution may result in a payment that is materially different from its current estimate of the tax liabilities. The Company’s assumptions, judgments and estimates relative to the value of a deferred tax asset take into account predictions of the amount and character of future taxable income, such as income from operations or capital gains income. Actual operating results and the underlying amount and character of income in future years could render the Company’s current assumptions, judgments and estimates of recoverable net deferred taxes inaccurate. Any of the assumptions, judgments and estimates mentioned above could cause the Company’s actual income tax obligations to differ from its estimates, thus materially impacting its financial condition and results of operations.
Stock-Based Compensation	Stock-based Compensation The Company’s stock-based compensation is primarily related to RSUs granted to employees and its employee stock purchase plan (“ESPP”). Stock-based compensation expense is typically recognized ratably over the requisite service period. Subsequent to the adoption of ASU No. 2016-09, Improvements to Employee Share-Based Payment Accounting on January 1, 2017, forfeitures of stock-based awards are no longer estimated at the time of grant but are recognized as they occur. The Company also grants RSUs which include performance conditions, and in some cases market conditions, to certain executives. The expense for these performance-based RSUs is recognized based on the probable outcome of the performance conditions. The expense recognized for awards with market conditions is based on the grant date fair value of the awards including the impact of the market conditions, using a Monte Carlo simulation model. The Company uses the Black-Scholes option pricing model to determine the fair value of its ESPP offerings. The determination of the fair value of stock-based payment awards using the Monte Carlo simulation model or the Black-Scholes option-pricing model is affected by the Company’s stock price as well as assumptions regarding a number of complex and subjective variables.
Earnings Per Share	Earnings per Share The Company computes basic earnings per share by dividing net income by the weighted-average number of common shares outstanding during the period. Diluted earnings per share gives effect to dilutive potential common shares, including outstanding stock options, unvested RSUs, ESPP offerings and the conversion spread related to the Subordinated Convertible Debentures using the treasury stock method.
Fair Value Of Financial Instruments	Fair Value of Financial Instruments The Company applies the following fair value hierarchy, which prioritizes the inputs used to measure fair value into three levels and bases the categorization within the hierarchy upon the lowest level of input that is available and significant to the fair value measurement: • Level 1: Observable inputs that reflect quoted prices (unadjusted) for identical assets or liabilities in active markets. • Level 2: Inputs reflect quoted prices for identical assets or liabilities in markets that are not active; quoted prices for similar assets or liabilities in active markets; inputs other than quoted prices that are observable for the assets or liabilities; or inputs that are derived principally from or corroborated by observable market data by correlation or other means. • Level 3: Unobservable inputs reflecting the Company’s own assumptions incorporated in valuation techniques used to determine fair value. These assumptions are required to be consistent with market participant assumptions that are reasonably available. The Company measures and reports certain financial assets and liabilities at fair value on a recurring basis, including its investments in money market funds classified as Cash and cash equivalents, marketable securities, and foreign currency forward contracts.
Commitments and Contingencies, Policy [Policy Text Block]	Legal Proceedings Verisign is involved in various investigations, claims and lawsuits arising in the normal conduct of its business, none of which, in its opinion, will have a material adverse effect on its financial condition, results of operations, or cash flows. The Company cannot assure you that it will prevail in any litigation. Regardless of the outcome, any litigation may require the Company to incur significant litigation expense and may result in significant diversion of management attention. While certain legal proceedings and related indemnification obligations to which the Company is a party specify the amounts claimed, such claims may not represent reasonably possible losses. Given the inherent uncertainties of the litigation, the ultimate outcome of these matters cannot be predicted at this time, nor can the amount of possible loss or range of loss, if any, be reasonably estimated, except in circumstances where an aggregate litigation accrual has been recorded for probable and reasonably estimable loss contingencies. A determination of the amount of accrual required, if any, for these contingencies is made after careful analysis of each matter. The required accrual may change in the future due to new developments in each matter or changes in approach such as a change in settlement strategy in dealing with these matters. The Company does not believe that any such matter currently being reviewed will have a material adverse effect on its financial condition, results of operations, or cash flows.
New Accounting Pronouncements, Policy [Policy Text Block]	Adoption of New Accounting Standards Effective January 1, 2017, the Company adopted Accounting Standards Update (“ASU”) No. 2016-09, Improvements to Employee Share-Based Payment Accounting, issued by the Financial Accounting Standards Board (“FASB”). The new guidance requires excess tax benefits and tax deficiencies to be recorded as a discrete adjustment to income tax expense when stock awards vest, rather than in additional paid-in capital when they reduce income taxes payable. The Company also made the accounting policy election, as allowed by the new guidance, to account for forfeitures of stock awards as they occur, rather than estimating forfeitures. These changes were required to be applied on a modified retrospective basis through a cumulative-effect adjustment to the opening balance of retained earnings. The cumulative effect of adopting ASU 2016-09 was an increase in Deferred tax assets of $ 11.0 million , a decrease in Deferred tax liabilities of $ 24.4 million , an increase in Additional paid-in capital of $ 2.5 million , and a decrease in Accumulated deficit of $ 32.9 million , as of January 1, 2017, as a result of recognizing $ 35.4 million of previously unrecognized excess tax benefits from stock-based compensation, and a $ 2.5 million adjustment related to the change in accounting policy for forfeitures. Additionally, the new guidance requires cash flows related to excess tax benefits from stock-based compensation to be recognized with other income tax cash flows in operating activities, rather than separately as a financing activity. The Company elected to apply this new cash flow presentation requirement retrospectively, which resulted in an increase to both net cash from operating activities and net cash used in financing activities of $ 25.1 million and $ 18.5 million for the years ended December 31, 2016 and 2015, respectively. Effective January 1, 2017, the Company adopted ASU 2017-04, Simplifying the Test for Goodwill Impairment , which was issued by the FASB. The guidance in the ASU simplifies certain aspects of the goodwill impairment test, including the elimination of the requirement to perform a qualitative assessment of the likelihood of a goodwill impairment for reporting units with a negative carrying value. All of the Company’s goodwill is included in the Registry Services reporting unit which has a negative carrying value. As a result, the Company will no longer be required to perform the qualitative assessment. Recent Accounting Pronouncements On May 28, 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers , which requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. The ASU will replace most existing revenue recognition guidance in U.S. GAAP when it becomes effective. The new standard will be effective for the Company’s 2018 fiscal year. The FASB also issued several amendments to the standard, including clarification on accounting for licenses of intellectual property and identifying performance obligations. Upon adoption the Company will record an asset of $ 27.3 million related to fees paid to ICANN for registrations and renewals of domain names ending in . com. These costs have historically been recognized as expense in the period of the registration or renewal but the Company has determined that they represent costs incurred to obtain a contract under the new guidance and will be capitalized and amortized over the respective domain terms beginning in 2018. The standard will be adopted on a modified retrospective basis and recorded as a cumulative effect adjustment to Accumulated deficit on January 1, 2018. This adjustment will be reflected in the financial statements included in our Form 10-Q for the three months ended March 31, 2018. Apart from this adjustment and the inclusion of the additional required disclosures, the Company does not expect the adoption of the new revenue standard to impact its consolidated financial statements. In February 2016, the FASB issued ASU No. 2016-02, Leases. The guidance introduces a lessee model that requires most leases to be reported on the balance sheet. This ASU will become effective for the Company on January 1, 2019 and requires the modified retrospective transition method. Based on its current portfolio of leases, the Company does not expect the adoption of this standard to have a material impact on its consolidated financial statements.

Financial Instruments (Tables)

Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2017
Cash, Cash Equivalents And Marketable Securities [Abstract]
Cash, Cash Equivalents, And Marketable Securities	The following table summarizes the Company’s cash, cash equivalents, and marketable securities and the fair value categorization of the financial instruments measured at fair value on a recurring basis: As of December 31, 2017 2016 (In thousands) Cash $ 135,092 $ 39,183 Time deposits 3,682 4,632 Money market funds (Level 1) 116,068 134,790 Debt securities issued by the U.S. Treasury and other U.S. government corporations and agencies (Level 1) 2,169,172 1,626,764 Equity securities of public companies (Level 1) 25 2,174 Total $ 2,424,039 $ 1,807,543 Included in Cash and cash equivalents $ 465,851 $ 231,945 Included in Marketable securities 1,948,900 1,565,962 Included in Other assets (Restricted cash) 9,288 9,636 Total $ 2,424,039 $ 1,807,543

Other Balance Sheet Items (Tabl

Other Balance Sheet Items (Tables)	12 Months Ended
	Dec. 31, 2017
Balance Sheet Related Disclosures [Abstract]
Prepaid Expenses And Other Current Assets	Other current assets consist of the following: As of December 31, 2017 2016 (In thousands) Prepaid expenses $ 15,787 $ 14,385 Accounts receivable, net 5,111 13,051 Income taxes receivable 6,347 15,328 Other 4,157 1,671 Total other current assets $ 31,402 $ 44,435
Property And Equipment, Net	The following table presents the detail of property and equipment, net: As of December 31, 2017 2016 (In thousands) Land $ 31,141 $ 31,141 Buildings and building improvements 246,654 246,237 Computer equipment and software 462,469 441,732 Capital work in progress 4,024 4,246 Office equipment and furniture 6,472 6,203 Leasehold improvements 1,403 1,350 Total cost 752,163 730,909 Less: accumulated depreciation (488,650 ) (464,784 ) Total property and equipment, net $ 263,513 $ 266,125
Goodwill	The following table presents the detail of goodwill: As of December 31, 2017 2016 (In thousands) Goodwill, gross $ 1,537,843 $ 1,537,843 Accumulated goodwill impairment (1,485,316 ) (1,485,316 ) Total goodwill $ 52,527 $ 52,527
Other Long-Term Assets	Other long-term assets consist of the following: As of December 31, 2017 2016 (In thousands) Long-term restricted cash 9,288 9,636 Other taxes receivable 5,673 5,673 Long-term prepaid expenses and other assets 3,642 3,884 Total other long-term assets $ 18,603 $ 19,193
Components Of Accounts Payable And Accrued Liabilities	Accounts payable and accrued liabilities consist of the following: As of December 31, 2017 2016 (In thousands) Accounts payable $ 20,923 $ 19,455 Accrued employee compensation 51,481 61,426 Customer deposits, net 63,617 52,173 Interest Payable 47,357 27,701 Taxes payable and other tax liabilities 13,477 23,144 Other accrued liabilities 22,748 20,021 Total accounts payable and accrued liabilities $ 219,603 $ 203,920

Debt And Interest Expense (Tabl

Debt And Interest Expense (Tables)	12 Months Ended
	Dec. 31, 2017
Debt Disclosure [Abstract]
Schedule of Debt [Table Text Block]	The following table summarizes information related to our Senior notes (in thousands, except interest rates): As of December 31, 2017 2016 Issuance Date Maturity Date Interest Rate Principal Senior notes due 2023 April 16, 2013 May 1, 2023 4.625 % $ 750,000 $ 750,000 Senior notes due 2025 March 27, 2015 April 1, 2025 5.250 % 500,000 500,000 Senior notes due 2027 July 5, 2017 July 15, 2027 4.750 % 550,000 — Unamortized issuance costs (17,471 ) (12,811 ) Total senior notes $ 1,782,529 $ 1,237,189
Proceeds upon issuance of the Convertible Debentures	Proceeds upon issuance of the Subordinated Convertible Debentures were as follows (in thousands): Principal value of Subordinated Convertible Debentures $ 1,250,000 Less: Issuance costs (25,777 ) Net proceeds, Subordinated Convertible Debentures $ 1,224,223 Amounts recognized at issuance: Subordinated Convertible Debentures, including contingent interest derivative (net of issuance costs of $11,328) $ 546,915 Additional paid-in capital 418,996 Long-term deferred tax liabilities 267,225 Non-operating loss (8,913 ) Net proceeds, Subordinated Convertible Debentures $ 1,224,223
Schedule of Carrying Amounts of Liability and Equity Components	The table below presents the carrying amounts of the liability and equity components: As of December 31, 2017 2016 (In thousands) Debt discount upon issuance (net of issuance costs of $14,449) $ 686,221 $ 686,221 Deferred taxes associated with the debt discount upon issuance (267,225 ) (267,225 ) Carrying amount of equity component $ 418,996 $ 418,996 Principal amount of Subordinated Convertible Debentures $ 1,250,000 $ 1,250,000 Unamortized discount of liability component (612,303 ) (624,315 ) Unamortized debt issuance costs associated with the liability component (10,081 ) (10,260 ) Carrying amount of liability component 627,616 615,425 Contingent interest derivative — 14,339 Subordinated Convertible Debentures, including contingent interest derivative $ 627,616 $ 629,764
Schedule of Components of Interest Expense	The following table presents the components of the Company’s interest expense: Year Ended December 31, 2017 2016 2015 (In thousands) Contractual interest on Subordinated Convertible Debentures $ 47,432 $ 40,625 $ 40,625 Contractual interest on Senior Notes 73,638 60,938 54,667 Amortization of debt discount on the Subordinated Convertible Debentures 12,012 11,094 10,218 Amortization of debt issuance costs and other interest expense 3,254 2,907 2,121 Total interest expense $ 136,336 $ 115,564 $ 107,631

Stockholders' Deficit Stockhold

Stockholders' Deficit Stockholders' Deficit (Equity) (Tables)	12 Months Ended
	Dec. 31, 2017
Stockholders' Equity Note [Abstract]
Schedule of Common Stock Repurchase	The summary of the Company’s common stock repurchases for 2017 , 2016 and 2015 are as follows: 2017 2016 2015 Shares Average Price Shares Average Price Shares Average Price (In thousands, except average price amounts) Total repurchases under the repurchase plans 6,265 $ 94.59 7,789 $ 81.73 9,338 $ 66.59 Total repurchases for tax withholdings 335 $ 85.27 320 $ 80.74 333 $ 64.03 Total repurchases 6,600 $ 94.12 8,109 $ 81.70 9,671 $ 66.50 Total costs $ 621,173 $ 662,491 $ 643,169
Schedule of Accumulated Other Comprehensive Loss	The following table summarizes the changes in the components of Accumulated other comprehensive loss for 2017 and 2016 : Foreign Currency Translation Adjustments Loss Unrealized (Loss) Gain On Investments Total Accumulated Other Comprehensive Loss (In thousands) Balance, December 31, 2015 $ (3,451 ) $ (542 ) $ (3,993 ) Changes 85 455 540 Balance, December 31, 2016 (3,366 ) (87 ) (3,453 ) Changes 530 (18 ) 512 Balance, December 31, 2017 $ (2,836 ) $ (105 ) $ (2,941 )

Calculation Of Net Income Per23

Calculation Of Net Income Per Share (Tables)	12 Months Ended
	Dec. 31, 2017
Earnings Per Share [Abstract]
Schedule of Weighted Average Number of Shares [Table Text Block]	The following table presents the computation of weighted-average shares used in the calculation of basic and diluted earnings per share: Year Ended December 31, 2017 2016 2015 (In thousands) Weighted-average shares of common stock outstanding 100,325 107,001 114,155 Weighted-average potential shares of common stock outstanding: Conversion spread related to Subordinated Convertible Debentures 23,247 21,074 18,047 Unvested RSUs, and ESPP 608 758 829 Shares used to compute diluted earnings per share 124,180 128,833 133,031

Geographic And Customer Infor24

Geographic And Customer Information (Tables)	12 Months Ended
	Dec. 31, 2017
Segment Reporting [Abstract]
Comparison of Geographic Revenues	The following table presents a comparison of the Company’s geographic revenues: Year Ended December 31, 2017 2016 2015 (In thousands) U.S $ 694,759 $ 667,301 $ 639,170 EMEA 211,349 207,474 193,623 China 106,526 127,298 83,456 Other 152,461 140,094 143,117 Total revenues $ 1,165,095 $ 1,142,167 $ 1,059,366
Comparison of Property and Equipment, Net, by Geographic Region	The following table presents a comparison of property and equipment, net of accumulated depreciation, by geographic region: As of December 31, 2017 2016 (In thousands) U.S. $ 258,231 $ 261,837 Other 5,282 4,288 Total property and equipment, net $ 263,513 $ 266,125

Employee Benefits And Stock-B25

Employee Benefits And Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2017
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Classification Of Stock-Based Compensation	The following table presents the classification of stock-based compensation: Year Ended December 31, 2017 2016 2015 (In thousands) Cost of revenues $ 7,030 $ 7,253 $ 7,009 Sales and marketing 5,688 5,738 6,763 Research and development 6,113 6,739 6,488 General and administrative 34,076 30,314 25,815 Total stock-based compensation $ 52,907 $ 50,044 $ 46,075
Nature Of Total Stock-Based Compensation	The following table presents the nature of the Company’s total stock-based compensation: Year Ended December 31, 2017 2016 2015 (In thousands) RSUs $ 38,087 $ 37,325 $ 36,664 Performance-based RSUs 13,270 11,512 8,078 ESPP 4,005 3,593 4,051 Capitalization (Included in Property and equipment, net) (2,455 ) (2,386 ) (2,718 ) Total stock-based compensation expenses $ 52,907 $ 50,044 $ 46,075
Summary Of Unvested RSUs Activity	The following table summarizes unvested RSUs activity: Year Ended December 31, 2017 2016 2015 Shares Weighted-Average Grant-Date Fair Value Shares Weighted-Average Grant-Date Fair Value Shares Weighted-Average Grant-Date Fair Value (Shares in thousands) Unvested at beginning of period 1,846 $ 66.30 2,110 $ 54.77 2,179 $ 46.36 Granted 732 79.94 760 78.58 1,075 61.74 Vested and settled (885 ) 61.75 (873 ) 49.95 (932 ) 43.92 Forfeited (105 ) 72.90 (151 ) 61.57 (212 ) 51.47 1,588 $ 74.69 1,846 $ 66.30 2,110 $ 54.77

Non-operating income, net Non-o

Non-operating income, net Non-operating income, net (Tables)	12 Months Ended
	Dec. 31, 2017
Non-operating (loss) income, net [Abstract]
Schedule of Non-operating Income, net	The following table presents the components of Non-operating income (loss), net: Year Ended December 31, 2017 2016 2015 (In thousands) Interest income $ 17,944 $ 6,191 $ 2,128 Gain on sale of business 10,421 — — Unrealized (loss) gain on contingent interest derivative on Subordinated Convertible Debentures (893 ) 2,402 (14,130 ) Other, net 154 1,572 1,337 Total non-operating income (loss), net $ 27,626 $ 10,165 $ (10,665 )

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2017
Income Taxes [Abstract]
Income From Continuing Operations Before Income Taxes	Income before income taxes is categorized geographically as follows: Year Ended December 31, 2017 2016 2015 (In thousands) United States $ 313,351 $ 299,304 $ 248,932 Foreign 285,661 281,869 238,718 Total income before income taxes $ 599,012 $ 581,173 $ 487,650
Components Of Provision For Income Taxes	The provision for income taxes consisted of the following: Year Ended December 31, 2017 2016 2015 (In thousands) Current expense: Federal $ 16,870 $ 34,842 $ 13,601 State 294 240 156 Foreign, including withholding tax 15,539 19,268 17,241 32,703 54,350 30,998 Deferred expense (benefit): Federal 90,113 64,301 65,168 State 19,654 21,492 15,767 Foreign (706 ) 385 481 109,061 86,178 81,416 Total income tax expense $ 141,764 $ 140,528 $ 112,414
Reconciliation Of Income Tax At Effective Income Tax Rate	The difference between income tax expense and the amount resulting from applying the federal statutory rate of 35% to Income before income taxes is attributable to the following: Year Ended December 31, 2017 2016 2015 (In thousands) Income tax expense at federal statutory rate $ 209,654 $ 203,410 $ 170,677 State taxes, net of federal benefit 13,029 14,517 9,616 Differences between statutory rate and foreign effective tax rate (83,808 ) (79,087 ) (66,238 ) U.S. federal tax rate change (186,800 ) — — U.S. tax on accumulated foreign earnings, net of foreign tax credits 162,353 — — Foreign withholding tax on unremitted foreign earnings, net of foreign tax credits 33,619 — — Other (6,283 ) 1,688 (1,641 ) Total income tax expense $ 141,764 $ 140,528 $ 112,414
Summary Of Deferred Tax Assets And Liabilities	The tax effects of temporary differences that give rise to significant portions of the Company’s deferred tax assets and liabilities are as follows: As of December 31, 2017 2016 (In thousands) Deferred tax assets: Net operating loss carryforwards $ 70,587 $ 46,879 Deductible goodwill and intangible assets 1,192 10,473 Tax credit carryforwards 52,659 59,337 Deferred revenue, accruals and reserves 77,869 114,548 Capital loss carryforwards 778,430 1,161,772 Other 5,584 4,791 Total deferred tax assets 986,321 1,397,800 Valuation allowance (783,725 ) (1,162,101 ) Net deferred tax assets 202,596 235,699 Deferred tax liabilities: Property and equipment (1,577 ) (4,212 ) U.S. tax on accumulated foreign earnings (162,912 ) — Foreign withholding tax on unremitted earnings (33,619 ) — Subordinated Convertible debentures (430,088 ) (590,921 ) Other (3,116 ) (2,614 ) Total deferred tax liabilities (631,312 ) (597,747 ) Total net deferred tax liabilities $ (428,716 ) $ (362,048 )
Reconciliation Of Gross Unrecognized Tax Benefits	A reconciliation of the beginning and ending balances of the total amounts of gross unrecognized tax benefits is as follows: As of December 31, 2017 2016 (In thousands) Beginning balance $ 220,682 $ 220,280 Increases in tax positions for prior years 3,699 119 Decreases in tax positions for prior years (144 ) (71 ) Increases in tax positions for current year 395 354 Decreases in tax positions due to settlement with taxing authorities (1,416 ) — Ending balance $ 223,216 $ 220,682

Commitments And Contingencies (

Commitments And Contingencies (Tables)	12 Months Ended
	Dec. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Minimum Payments Required Under Purchase Obligations	The following table represents the minimum payments required by Verisign under certain purchase obligations, leases, the .tv Agreement with the Government of Tuvalu, and the interest payments and principal on the Subordinated Convertible Debentures and the Senior Notes: Purchase Obligations .tv Agreement Senior Notes Subordinated Convertible Debentures Total (In thousands) 2018 $ 33,175 $ 5,000 $ 87,063 $ 1,279,388 $ 1,404,626 2019 4,893 5,000 87,063 — 96,956 2020 806 5,000 87,063 — 92,869 2021 612 5,000 87,063 — 92,675 2022 301 — 87,063 — 87,364 Thereafter — — 2,030,938 — 2,030,938 Total $ 39,787 $ 20,000 $ 2,466,253 $ 1,279,388 $ 3,805,428

Description Of Business And S29

Description Of Business And Summary Of Significant Accounting Policies (Narrative) (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Aug. 31, 2007	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Jan. 01, 2017	Aug. 15, 2007
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Capitalized Computer Software, Additions		$ 17,700	$ 18,000
Convertible debenture, interest rate						3.25%
Convertible debenture, maturity date	Aug. 15, 2037
Net remeasurement gain (loss) on foreign currency translation		1,000	1,000
Gains (losses) on foreign currency forward contracts		1,000	1,000
Advertising expenses		27,400	17,200	$ 16,000
Derivative, Notional Amount		29,700
Deferred Tax Liabilities, Net, Noncurrent		444,108	371,433
Deferred Tax Liabilities, Other		3,116	2,614
Deferred Tax Asset for previously unrecognized excess tax benefits		35,400
excess tax benefit related to stock based compensation			$ 25,100	$ 18,500
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification		$ 27,300
Building Improvements [Member]
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of property and equipment (years)		10 years
Maximum [Member]
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
RegistrationTerm		10 years
Average Service Term		2 years
Maximum [Member] | Buildings [Member]
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of property and equipment (years)		47 years
Maximum [Member] | Computer Equipment, Purchased Software, Office Equipment, And Furniture And Fixtures [Member]
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of property and equipment (years)		5 years
Minimum [Member]
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
RegistrationTerm		1 year
Average Service Term		1 year
Minimum [Member] | Buildings [Member]
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of property and equipment (years)		35 years
Minimum [Member] | Computer Equipment, Purchased Software, Office Equipment, And Furniture And Fixtures [Member]
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of property and equipment (years)		3 years
Deferred Tax Asset [Domain]
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption					$ 11,000
Additional Paid-in Capital [Member]
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption					2,544
Retained Earnings [Member]
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption					32,916
Long-term deferred tax liability [member]
Description Of Business And Summary Of Significant Accounting Policies [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption					$ 24,400

Financial Instruments (Details)

Financial Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Cash	$ 135,092	$ 39,183
Money market funds	3,682	4,632
Time deposits	116,068	134,790
Available-for-sale Securities, Debt Maturities, Next Twelve Months, Fair Value	2,169,172	1,626,764
Available-for-sale Securities, Equity Securities	25	2,174
Total	2,424,039	1,807,543
Included in Cash and cash equivalents	465,851	231,945	$ 228,659	$ 191,608
Included in Marketable securities	1,948,900	1,565,962
Included in Other assets (Restricted cash)	$ 9,288	$ 9,636

Financial Instruments Financial

Financial Instruments Financial Instruments narrative (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument, Fair Value Disclosure	$ 4,200,000
Available-for-sale Securities, Debt Maturities, Next Twelve Months, Fair Value	2,169,172	$ 1,626,764
Available-for-sale Debt Securities Gross Unrealized Gain	1,000
Due 2023 [Member]
Debt Instrument, Fair Value Disclosure	772,900
Due 2025 [Member]
Debt Instrument, Fair Value Disclosure	544,400
Due 2027 [Member]
Debt Instrument, Fair Value Disclosure	$ 563,700

Other Balance Sheet Items (Prep

Other Balance Sheet Items (Prepaid Expenses And Other Current Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Balance Sheet Related Disclosures [Abstract]
Prepaid expenses	$ 15,787	$ 14,385
Accounts Receivable, Net, Current	5,111	13,051
Income Taxes Receivable	6,347	15,328
Other	4,157	1,671
Other current assets	$ 31,402	$ 44,435

Other Balance Sheet Items (Prop

Other Balance Sheet Items (Property And Equipment, Net) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Land	$ 31,141	$ 31,141
Buildings and building improvements	246,654	246,237
Computer equipment and software	462,469	441,732
Capital work in progress	4,024	4,246
Office equipment and furniture	6,472	6,203
Leasehold improvements	1,403	1,350
Total cost	752,163	730,909
Less: accumulated depreciation and amortization	(488,650)	(464,784)
Total property and equipment, net	$ 263,513	$ 266,125

Other Balance Sheet Items Other

Other Balance Sheet Items Other Balance Sheet Items (Goodwill) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Balance Sheet Related Disclosures [Abstract]
Goodwill, Gross	$ 1,537,843	$ 1,537,843
Goodwill, Impaired, Accumulated Impairment Loss	(1,485,316)	(1,485,316)
Goodwill	$ 52,527	$ 52,527

Other Balance Sheet Items Oth35

Other Balance Sheet Items Other balance Sheet items (Other long-term assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Balance Sheet Related Disclosures [Abstract]
Restricted Cash	$ 9,288	$ 9,636
Nontrade Receivables, Noncurrent	5,673	5,673
Prepaid Expense and Other Assets, Noncurrent	3,642	3,884
Total other long-term assets	$ 18,603	$ 19,193

Other Balance Sheet Items (Comp

Other Balance Sheet Items (Components Of Accounts Payable And Accrued Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Balance Sheet Related Disclosures [Abstract]
Accounts payable	$ 20,923	$ 19,455
Accrued employee compensation	51,481	61,426
Customer deposits, net	63,617	52,173
Interest Payable	47,357	27,701
Taxes payable and other tax liabilities	13,477	23,144
Other accrued liabilities	22,748	20,021
Total accounts payable and accrued liabilities	$ 219,603	$ 203,920

Other Balance Sheet Items (Narr

Other Balance Sheet Items (Narrative) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Deposits Assets, Noncurrent	$ 145,000	$ 145,000

Debt And Interest Expense Debt

Debt And Interest Expense Debt and Interest Expense (Senior Notes) (Narrative) (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended	12 Months Ended
	Aug. 31, 2007	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Aug. 15, 2007
Debt Instrument [Line Items]
Senior Notes			$ 1,782,529	$ 1,237,189
Debt Instrument, Face Amount			1,250,000	1,250,000	$ 1,250,000
Debt Instrument, Interest Rate, Stated Percentage					3.25%
Debt Instrument, Maturity Date		Apr. 1, 2020
issuance cost on senior note			$ (17,471)	(12,811)
Net proceeds from issuance of convertible debenture	$ 1,224,223
Due 2027 [Member]
Debt Instrument [Line Items]
Debt Instrument, Offering Date			Jul. 5, 2017
Debt Instrument, Face Amount			$ 550,000	$ 0
Debt Instrument, Interest Rate, Stated Percentage			4.75%
Debt Instrument, Maturity Date			Jul. 15, 2027

Debt And Interest Expense (Cred

Debt And Interest Expense (Credit Facilities) (Narrative) (Details)	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2017USD ($)
Debt Instrument [Line Items]
Borrowing capacity of senior unsecured revolving credit facility		$ 200,000,000
Credit facility, maturity date	Apr. 1, 2020
Aggregate increase of commitment amount available		$ 150,000,000
Minimum [Member]
Debt Instrument [Line Items]
Interest coverage ratio		3
Maximum [Member]
Debt Instrument [Line Items]
Leverage ratio		2.5

Debt And Interest Expense (Conv

Debt And Interest Expense (Convertible Debentures) (Narrative) (Details) $ / shares in Units, shares in Millions	1 Months Ended	3 Months Ended	12 Months Ended
	Aug. 31, 2007USD ($)Rate	Dec. 31, 2017USD ($)$ / sharesshares	Dec. 31, 2017USD ($)Rateshares	Dec. 31, 2016USD ($)	Aug. 15, 2007USD ($)$ / sharesRate
Debt Disclosure [Abstract]
Principal amount of debt | $		$ 1,250,000,000	$ 1,250,000,000	$ 1,250,000,000	$ 1,250,000,000
Convertible debenture, interest rate					3.25%
Convertible debenture, maturity date	Aug. 15, 2037
Conversion rate per 1000 principal amount	29.0968
Denominator of principal value upon which conversion is based | $	$ 1,000
Conversion price | $ / shares					$ 34.37
stock reserved for issuance | shares		36.4	36.4
Minimum required sales price as a percentage of conversion price	150.00%
Debt Instrument, Convertible, Stock Price Trigger | $ / shares		$ 44.68
Additional common shares potentially issuable based on if-converted value of convertible debentures | shares			25.4
Debt issuance costs | $	$ 25,777,000
Discount rate	8.50%		8.50%
Debt Instrument, Convertible, Remaining Discount Amortization Period			19 years 227 days
Effective interest rate					8.39%

Debt And Interest Expense Deb41

Debt And Interest Expense Debt And Interest Expense (Proceeds Upon Issuance Of Convertible Debt) (Details) $ in Thousands	1 Months Ended
	Aug. 31, 2007USD ($)
Debt Instrument [Line Items]
Debt Instrument, Face Amount	$ 1,250,000
Payments of Debt Issuance Costs	(25,777)
Proceeds from Convertible Debt	1,224,223
Convertible Debt [Member]
Debt Instrument [Line Items]
Proceeds from Convertible Debt	546,915
Additional Paid-in Capital [Member]
Debt Instrument [Line Items]
Proceeds from Convertible Debt	418,996
Long-term deferred tax liability [member]
Debt Instrument [Line Items]
Proceeds from Convertible Debt	267,225
Other Expense [Member]
Debt Instrument [Line Items]
Proceeds from Convertible Debt	$ (8,913)

Debt And Interest Expense (Carr

Debt And Interest Expense (Carrying Amounts Of Liability And Equity Components) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Aug. 15, 2007
Debt Disclosure [Abstract]
Debt Instrument, Unamortized Discount (Premium), Net	$ 686,221	$ 686,221
deferred tax on debenture discount	(267,225)	(267,225)
Carrying amount of equity component (net of issuance costs of $14,449)	418,996	418,996
Principal amount of debt	1,250,000	1,250,000	$ 1,250,000
Unamortized discount of liability component	(612,303)	(624,315)
Unamortized Debt Issuance Expense	(10,081)	(10,260)
Carrying amount of liability component	627,616	615,425
Contingent interest derivative	0	14,339
Convertible Debt	$ 627,616	$ 629,764

Debt And Interest Expense (Comp

Debt And Interest Expense (Components Of Interest Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Short-term Debt [Line Items]
Contractual interest on Convertible Debentures	$ 47,432	$ 40,625	$ 40,625
Interest Expense, Debt	73,638	60,938	54,667
Amortization of debt discount on the Convertible Debentures	12,012	11,094	10,218
Other interest expense	3,254	2,907	2,121
Total interest expense	$ 136,336	$ 115,564	$ 107,631

Debt And Interest Expense Deb44

Debt And Interest Expense Debt and Interest Expense (Senior Notes) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Aug. 15, 2007
Debt Instrument [Line Items]
Debt Instrument, Maturity Date	Apr. 1, 2020
Debt Instrument, Interest Rate, Stated Percentage				3.25%
Debt Instrument, Face Amount		$ 1,250,000	$ 1,250,000	$ 1,250,000
issuance cost on senior note		(17,471)	(12,811)
Senior Notes		$ 1,782,529	1,237,189
Due 2023 [Member]
Debt Instrument [Line Items]
Debt Instrument, Offering Date		Apr. 16, 2013
Debt Instrument, Maturity Date		May 1, 2023
Debt Instrument, Interest Rate, Stated Percentage		4.625%
Debt Instrument, Face Amount		$ 750,000	750,000
Due 2025 [Member]
Debt Instrument [Line Items]
Debt Instrument, Offering Date		Mar. 27, 2015
Debt Instrument, Maturity Date		Apr. 1, 2025
Debt Instrument, Interest Rate, Stated Percentage		5.25%
Debt Instrument, Face Amount		$ 500,000	500,000
Due 2027 [Member]
Debt Instrument [Line Items]
Debt Instrument, Offering Date		Jul. 5, 2017
Debt Instrument, Maturity Date		Jul. 15, 2027
Debt Instrument, Interest Rate, Stated Percentage		4.75%
Debt Instrument, Face Amount		$ 550,000	$ 0

Stockholders' (Deficit) Equity

Stockholders' (Deficit) Equity (Narrative) (Details) - USD ($) $ in Millions	1 Months Ended
	Feb. 08, 2018	Feb. 09, 2017	Dec. 31, 2017
Treasury Stock Repurchase Programs [Line Items]
Treasury Stock Shares Repurchased			227,600,000
Additional share repurchase amount authorized	$ 585.8	$ 640.9
Common stock authorized to repurchase	1,000	1,000
Remaining common stock available for repurchase	$ 414.2	$ 359.1
Payments for Repurchase of Common Stock			$ 8,800
Share Buyback Program [Member]
Treasury Stock Repurchase Programs [Line Items]
Remaining common stock available for repurchase			$ 477.4

Stockholders' Deficit Stockho46

Stockholders' Deficit Stockholders' (Deficit) Equity (Summary of Common Stock Repurchase) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Stockholders' Equity Note [Abstract]
Treasury Stock Shares Repurchased	6,265	7,789	9,338
Treasury Stock Shares Repurchased For Tax Withholdings And Other	335	320	333
Treasury Stock, Shares, Acquired	6,600	8,109	9,671
Treasury Stock Shares Repurchased, Average Cost Per Share	$ 94.59	$ 81.73	$ 66.59
Treasury stock shares repurchased for tax withholdings and other, average cost per share	85.27	80.74	64.03
Treasury Stock Acquired, Average Cost Per Share	$ 94.12	$ 81.70	$ 66.50
Payments for Repurchase of Common Stock	$ 621,173	$ 662,491	$ 643,169

Stockholders' Deficit Stockho47

Stockholders' Deficit Stockholders' (Deficit) Equity (Changes In Components Of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Stockholders' Equity Note [Abstract]
Foreign Currency Translation Adjustmentss Loss, Changes	$ 530	$ 85
Foreign Currency Translation Adjustment, Balance	(2,836)	(3,366)	$ (3,451)
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	(18)	455
Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	(105)	(87)	(542)
Other Comprehensive Income (Loss), Net of Tax	512	540	(995)
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ (2,941)	$ (3,453)	$ (3,993)

Calculation Of Net Income Per48

Calculation Of Net Income Per Share (Weighted-Average Shares Used In Calculation Of Basic And Diluted EPS) (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Earnings Per Share [Abstract]
Weighted-average number of common shares outstanding	100,325	107,001	114,155
Conversion spread related to Convertible Debentures	23,247	21,074	18,047
Unvested restricted stock units	608	758	829
Shares used to compute diluted net income per share	124,180	128,833	133,031

Geographic And Customer Infor49

Geographic And Customer Information (Narrative) (Details)	12 Months Ended
	Dec. 31, 2017Rate	Dec. 31, 2016Rate	Dec. 31, 2015Rate
Segment Reporting Information [Line Items]
Concentration risk, percentage	31.00%	30.00%	31.00%
Number of customers accounting for concentration of risk	1	1	1,000

Geographic And Customer Infor50

Geographic And Customer Information (Comparison Of Geographic Revenues) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	$ 1,165,095	$ 1,142,167	$ 1,059,366
U.S. [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	694,759	667,301	639,170
EMEA [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	211,349	207,474	193,623
Asia Pacific [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	106,526	127,298	83,456
Other [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	$ 152,461	$ 140,094	$ 143,117

Geographic And Customer Infor51

Geographic And Customer Information (Comparison Of Property And Equipment, Net, By Geographic Region) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property and equipment, net	$ 263,513	$ 266,125
U.S. [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property and equipment, net	258,231	261,837
EMEA [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total property and equipment, net	$ 5,282	$ 4,288

Employee Benefits And Stock-B52

Employee Benefits And Stock-Based Compensation (401(k) Plan To 2007 Employee Stock Purchase Plan) (Narrative) (Details) - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employer contribution as a percentage of employee's annual salary	6.00%
Employer contribution under the plan	$ 4	$ 3.8	$ 3.7
Common stock were reserved for issuance	10.5
Purchase price of common stock as percentage of lower of fair market value of common stock share on first day of offering period or last day of purchase period	85.00%
Employee Stock Ownership Plan (ESOP), Shares in ESOP	3.5
401 (k) Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee's contribution under the plan	50.00%
Share-Based Compensation Arrangement By Share-Based Payment Award, Employer Contribution As A Percentage Of Employee Contribution	50.00%
Two Thousand Seven Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock were reserved for issuance	8.5
Two Thousand Six Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock were reserved for issuance	27
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of compensation withheld to cover purchase price of common stock	2.00%
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of compensation withheld to cover purchase price of common stock	25.00%

Employee Benefits And Stock-B53

Employee Benefits And Stock-Based Compensation Employee Benefits and Stock-Based Compensation (Classification of Share-based Compensation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based Compensation	$ 52,907	$ 50,044	$ 46,075
Cost of Sales [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based Compensation	7,030	7,253	7,009
Selling and Marketing Expense [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based Compensation	5,688	5,738	6,763
Research and Development Expense [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based Compensation	6,113	6,739	6,488
General and Administrative Expense [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based Compensation	$ 34,076	$ 30,314	$ 25,815

Employee Benefits And Stock-B54

Employee Benefits And Stock-Based Compensation Employee Benefits And Stock-Based Compensation (Share-based Compensation by award type) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation	$ 52,907	$ 50,044	$ 46,075
Employee Service Share-based Compensation, Allocation of Recognized Period Costs, Capitalized Amount	(2,455)	(2,386)	(2,718)
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation	38,087	37,325	36,664
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation	13,270	11,512	8,078
Employee Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation	$ 4,005	$ 3,593	$ 4,051

Employee Benefits And Stock-B55

Employee Benefits And Stock-Based Compensation (Stock Based Compensation to Modifications) (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized	2,500,000
Employee Stock Ownership Plan (ESOP), Shares in ESOP	3,500,000
Closing price of Verisign's stock	$ 114.44
Income Tax Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Income tax benefit on stock-based compensation	$ 12.5	$ 17.7	$ 16
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation cost	$ 77.5
Weighted-average period of recognition for unrecognized compensation cost (in years)	2 years 6 months
Aggregate intrinsic value of unvested RSUs	$ 181.7
Fair values of vested RSUs	$ 75.9	$ 70.5	$ 59.8
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units with performance condition	400,000
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units with performance condition	0
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock units with performance condition	800,000

Employee Benefits And Stock-B56

Employee Benefits And Stock-Based Compensation (Summary Of Unvested RSUs Activity) (Details) - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested at beginning of period, Shares	1,846	2,110	2,179
Granted, Shares	732	760	1,075
Vested and settled, Shares	(885)	(873)	(932)
Forfeited, Shares	(105)	(151)	(212)
Unvested at end of period, Shares	1,588	1,846	2,110
Unvested at beginning of period, Weighted-Average Grant-Date Fair Value	$ 66.30	$ 54.77	$ 46.36
Granted, Weighted-Average Grant-Date Fair Value	79.94	78.58	61.74
Vested and settled, Weighted-Average Grant-Date Fair Value	61.75	49.95	43.92
Forfeited, Weighted-Average Grant-Date Fair Value	72.90	61.57	51.47
Unvested at end of period, Weighted-Average Grant-Date Fair Value	$ 74.69	$ 66.30	$ 54.77

Non-operating income, net Non57

Non-operating income, net Non-Operating income, net (Components of Non-operating income, net) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Non-operating (loss) income, net [Abstract]
Investment Income, Interest and Dividend	$ 17,944	$ 6,191	$ 2,128
Gain (Loss) on Disposition of Business	10,421	0	0
Unrealized Gain (Loss) on Derivatives	(893)	2,402	(14,130)
Other Nonoperating Income (Expense)	154	1,572	1,337
Nonoperating Income (Expense)	$ 27,626	$ 10,165	$ (10,665)

Non-operating income, net Non58

Non-operating income, net Non-Operating Income, net (Narrative) (Details) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Gain on Sale of Business [Abstract]
Gain (Loss) on Disposition of Business	$ 10,421	$ 0	$ 0

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	12 Months Ended
	Aug. 31, 2007	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Taxes [Line Items]
Federal statutory rate		35.00%	35.00%	35.00%
Federal income tax rate after enactment of Tax reform (Percentage)		21.00%
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount		$ 186,800	$ 0	$ 0
U.S tax on foreign earnings, net of foreign tax credits		$ 162,353	0	0
Deferred Tax Asset for previously unrecognized excess tax benefits		38.3
Deferred Tax Liability Not Recognized, Amount of Unrecognized Deferred Tax Liability, Undistributed Earnings of Foreign Subsidiaries		$ 33,600
Foreign tax credit related to withholding taxes		26,300
Foreign Withholding Tax		33,619	$ 0	$ 0
Alternative minimum tax credits		17,000
Tax Credit Carryforward, Amount		$ 121,500
Impact of tax holiday on diluted earnings per share		$ 0.10	$ 0.16	$ 0.14
Debt Instrument, Interest Rate, Stated Percentage		3.25%
Tax credit carryforward expiration		2018 through 2034
Debt Instruments, Discount Rate	8.50%	8.50%
Liability for Uncertain Tax Positions, Noncurrent		$ 217,000
Federal [Member]
Income Taxes [Line Items]
Net operating loss carryforwards		5,500
Federal research tax credits		4,200
capital loss carryforward		2,900,000
State [Member]
Income Taxes [Line Items]
Net operating loss carryforwards		1,300,000
Federal research tax credits		2,300
capital loss carryforward		3,100,000
Foreign [Member]
Income Taxes [Line Items]
Net operating loss carryforwards		$ 18,900
Tax credit carryforward expiration		2,024
Federal And State [Member]
Income Taxes [Line Items]
Operating Loss Carryforwards, Date		2018 through 2034

Income Taxes (Income From Conti

Income Taxes (Income From Continuing Operations Before Income Taxes) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Expense (Benefit), Continuing Operations [Abstract]
United States	$ 313,351	$ 299,304	$ 248,932
Foreign	285,661	281,869	238,718
Income from continuing operations before income taxes	$ 599,012	$ 581,173	$ 487,650

Income Taxes (Components Of Pro

Income Taxes (Components Of Provision For Income Taxes) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Expense (Benefit), Continuing Operations [Abstract]
Federal, Current (expense) benefit	$ (16,870)	$ (34,842)	$ (13,601)
State, Current (expense) benefit	(294)	(240)	(156)
Foreign, including foreign withholding tax, Current (expense) benefit	(15,539)	(19,268)	(17,241)
Current (expense) benefit	32,703	54,350	30,998
Federal, Deferred (expense) benefit	(90,113)	(64,301)	(65,168)
State, Deferred (expense) benefit	(19,654)	(21,492)	(15,767)
Foreign, Deferred (expense) benefit	706	(385)	(481)
Deferred (expense) benefit	109,061	86,178	81,416
Income tax (expense) benefit	$ 141,764	$ 140,528	$ 112,414

Income Taxes (Reconciliation Of

Income Taxes (Reconciliation Of Income Tax At Effective Income Tax Rate) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Expense (Benefit), Continuing Operations [Abstract]
Income tax expense at federal statutory rate	$ (209,654)	$ (203,410)	$ (170,677)
State taxes, net of federal benefit	(13,029)	(14,517)	(9,616)
Differences between statutory rate and foreign effective tax rate	83,808	79,087	66,238
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount	(186,800)	0	0
U.S tax on foreign earnings, net of foreign tax credits	162,353	0	0
Foreign Withholding Tax	33,619	0	0
Other	6,283	(1,688)	1,641
Income tax (expense) benefit	$ 141,764	$ 140,528	$ 112,414

Income Taxes (Summary Of Deferr

Income Taxes (Summary Of Deferred Tax Assets And Liabilities) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Expense (Benefit), Continuing Operations [Abstract]
Net operating loss carryforwards	$ 70,587	$ 46,879
Deductible goodwill and intangible assets	1,192	10,473
Tax credit carryforwards	52,659	59,337
Deferred revenue, accruals and reserves	77,869	114,548
Capital loss carryforwards and book impairment of investments	778,430	1,161,772
Other	5,584	4,791
Total deferred tax assets	986,321	1,397,800
Valuation allowance	(783,725)	(1,162,101)
Net deferred tax assets	202,596	235,699
Property and equipment	(1,577)	(4,212)
U.S tax on accumulated foreign earnings	(162,912)
U.S tax on foreign earnings, net of foreign tax credits	162,353	0	$ 0
foreign withholding tax on unremitted earnings	(33,619)	0
Convertible debentures	(430,088)	(590,921)
Other	(3,116)	(2,614)
Deferred Tax Liabilities, Gross	631,312	597,747
Total deferred tax liabilities	$ 428,716	$ 362,048

Income Taxes (Reconciliation 64

Income Taxes (Reconciliation Of Gross Unrecognized Tax Benefits) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Income Tax Expense (Benefit), Continuing Operations [Abstract]
Gross unrecognized tax benefits at January 1	$ 220,682	$ 220,280
Increases in tax positions for prior years	3,699	119
Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions	(144)	(71)
Increases in tax positions for current year	395	354
Gross unrecognized tax benefits at December 31	223,216	220,682
Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities	$ (1,416)	$ 0

Commitments And Contingencies65

Commitments And Contingencies (Narrative) (Details) number in Millions	12 Months Ended
	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Commitments And Contingencies [Line Items]
Number of domain names registered	131.9
Uncertain tax positions	$ 217,000,000
ICANN Agreement [Member]
Commitments And Contingencies [Line Items]
Expiration Date of Registry Agreement	Nov. 30, 2024
Registry fee per transaction	$ 0.25
Payments for registry fees	32,300,000	$ 31,500,000	$ 30,900,000
.TV Agreement [Member]
Commitments And Contingencies [Line Items]
renewed agreement fees	$ 5,000,000	$ 5,000,000	$ 5,000,000

Commitments And Contingencies66

Commitments And Contingencies (Minimum Payments Required Under Purchase Obligations) (Details) $ in Thousands	Dec. 31, 2017USD ($)
Purchase Obligations And Contractual Agreements [Line Items]
2,017	$ 1,404,626
2,018	96,956
2,019	92,869
2,020	92,675
2,021	87,364
Thereafter	2,030,938
Purchase Obligation	3,805,428
Purchase Obligations [Member]
Purchase Obligations And Contractual Agreements [Line Items]
2,017	33,175
2,018	4,893
2,019	806
2,020	612
2,021	301
Thereafter	0
Purchase Obligation	39,787
.TV Agreement [Member]
Purchase Obligations And Contractual Agreements [Line Items]
2,017	5,000
2,018	5,000
2,019	5,000
2,020	5,000
2,021	0
Thereafter	0
Purchase Obligation	20,000
Convertible Debt [Member]
Purchase Obligations And Contractual Agreements [Line Items]
2,017	1,279,388
2,018	0
2,019	0
2,020	0
2,021	0
Thereafter	0
Purchase Obligation	1,279,388
Senior Notes [Member]
Purchase Obligations And Contractual Agreements [Line Items]
2,017	87,063
2,018	87,063
2,019	87,063
2,020	87,063
2,021	87,063
Thereafter	2,030,938
Purchase Obligation	$ 2,466,253

Uncategorized Items - vrsn-2017

Label	Element	Value
Parent [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ 35,460,000