Condensed Consolidated Statements Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Balance at beginning of period (in shares) at Dec. 31, 2019		154,145,000
Balance at beginning of period at Dec. 31, 2019	$ 2,649,522	$ 154	$ 3,042,034	$ (5,247)	$ (387,419)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Foreign currency translation adjustment	(2,651)			(2,651)
Net income (loss)	13,260				13,260
Comprehensive income (loss)	10,609
Exercise of stock options (in shares)		141,000
Exercise of stock options	309		309
Restricted stock units issued, net of shares withheld for taxes (in shares)		329,000
Restricted stock units issued, net of shares withheld for taxes	(2,351)	$ 1	(2,352)
Issuance of stock (in shares)		591,000
Issuance of stock	660	$ 1	659
Issuance of stock under employee stock purchase plan (in shares)		80,000
Issuance of stock under employee stock purchase plan	2,357		2,357
Stock-based compensation	24,606		24,606
Balance at end of period (in shares) at Jun. 30, 2020		155,286,000
Balance at end of period at Jun. 30, 2020	2,685,712	$ 156	3,067,613	(7,898)	(374,159)
Balance at beginning of period (in shares) at Mar. 31, 2020		154,946,000
Balance at beginning of period at Mar. 31, 2020	2,632,364	$ 155	3,054,889	(35,676)	(387,004)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Foreign currency translation adjustment	27,778			27,778
Net income (loss)	12,845				12,845
Comprehensive income (loss)	40,623
Exercise of stock options (in shares)		112,000
Exercise of stock options	258		258
Restricted stock units issued, net of shares withheld for taxes (in shares)		190,000
Restricted stock units issued, net of shares withheld for taxes	(803)	$ 1	(804)
Issuance of stock (in shares)		38,000
Issuance of stock	31		31
Stock-based compensation	13,239		13,239
Balance at end of period (in shares) at Jun. 30, 2020		155,286,000
Balance at end of period at Jun. 30, 2020	$ 2,685,712	$ 156	3,067,613	(7,898)	(374,159)
Balance at beginning of period (in shares) at Dec. 31, 2020	156,519,611	156,520,000
Balance at beginning of period at Dec. 31, 2020	$ 3,010,687	$ 157	3,112,262	127,212	(228,944)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Foreign currency translation adjustment	(48,105)			(48,105)
Net income (loss)	(18,784)				(18,784)
Comprehensive income (loss)	(66,889)
Exercise of stock options (in shares)		92,000
Exercise of stock options	401		401
Restricted stock units issued, net of shares withheld for taxes (in shares)		848,000
Restricted stock units issued, net of shares withheld for taxes	(9,868)	$ 1	(9,869)
Issuance of stock (in shares)		447,000
Issuance of stock	492		492
Issuance of stock under employee stock purchase plan (in shares)		108,000
Issuance of stock under employee stock purchase plan	3,129		3,129
Stock-based compensation	$ 33,761		33,761
Balance at end of period (in shares) at Jun. 30, 2021	158,014,531	158,015,000
Balance at end of period at Jun. 30, 2021	$ 2,971,713	$ 158	3,140,176	79,107	(247,728)
Balance at beginning of period (in shares) at Mar. 31, 2021		157,702,000
Balance at beginning of period at Mar. 31, 2021	2,950,166	$ 158	3,124,650	61,462	(236,104)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Foreign currency translation adjustment	17,645			17,645
Net income (loss)	(11,624)				(11,624)
Comprehensive income (loss)	6,021
Exercise of stock options (in shares)		88,000
Exercise of stock options	390		390
Restricted stock units issued, net of shares withheld for taxes (in shares)		189,000
Restricted stock units issued, net of shares withheld for taxes	(1,471)		(1,471)
Issuance of stock (in shares)		36,000
Issuance of stock	29		29
Stock-based compensation	$ 16,578		16,578
Balance at end of period (in shares) at Jun. 30, 2021	158,014,531	158,015,000
Balance at end of period at Jun. 30, 2021	$ 2,971,713	$ 158	$ 3,140,176	$ 79,107	$ (247,728)