Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Treasury Stock	Accumulated Deficit
Beginning balance (in shares) at Dec. 31, 2018		162,904,550
Beginning Balance at Dec. 31, 2018	$ 3,191,860	$ 1,629	$ 3,670,033	$ (48,912)	$ 0	$ (430,890)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon the exercise of stock options and vesting of restricted and deferred stock units, net of shares withheld for employee taxes (in shares)		1,090,658
Issuance of common stock upon the exercise of stock options and vesting of restricted and deferred stock units, net of shares withheld for employee taxes	(37,764)	$ 11	(37,775)
Stock-based compensation	54,079		54,079
Repurchases of common stock (in shares)		(491,950)
Repurchases of common stock	(34,872)				(34,872)
Net income	107,130					107,130
Foreign currency translation adjustment	502			502
Change in unrealized loss on investments, net of tax	1,431			1,431
Ending balance (in shares) at Mar. 31, 2019		163,503,258
Ending Balance at Mar. 31, 2019	3,283,217	$ 1,640	3,686,337	(46,979)	(34,872)	(322,909)
Beginning balance (in shares) at Dec. 31, 2019		162,000,843
Beginning Balance at Dec. 31, 2019	3,657,958	$ 1,620	3,653,486	(45,144)	0	47,996
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon the exercise of stock options and vesting of restricted and deferred stock units, net of shares withheld for employee taxes (in shares)		1,047,040
Issuance of common stock upon the exercise of stock options and vesting of restricted and deferred stock units, net of shares withheld for employee taxes	(50,700)	$ 11	(50,711)
Stock-based compensation	56,215		56,215
Repurchases of common stock (in shares)		(871,294)
Repurchases of common stock	(80,550)				(80,550)
Net income	123,146					123,146
Foreign currency translation adjustment	(26,277)			(26,277)
Change in unrealized loss on investments, net of tax	(7,574)			(7,574)
Ending balance (in shares) at Mar. 31, 2020		162,176,589
Ending Balance at Mar. 31, 2020	$ 3,672,218	$ 1,631	$ 3,658,990	$ (78,995)	$ (80,550)	$ 171,142