CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Common Stock [Member]	Additional Paid In Capital [Member]	Accumulated Other Comprehensive Loss [Member]	Accumulated Deficit [Member]	Total
Balance at Dec. 31, 2020	$ 140	$ 1,895,519	$ (21,071)	$ (1,131,306)	$ 743,282
Balance (in shares) at Dec. 31, 2020	140,366
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	$ 0	0	0	(89,869)	(89,869)
Change in unrealized losses, net of tax	0	0	(3,006)	0	(3,006)
Foreign currency translation	0	0	(126)	0	(126)
Issuance of common stock in connection with employee stock plans	$ 1	7,758	0	0	7,759
Issuance of common stock in connection with employee stock plans (in shares)	809
Stock-based compensation expense	$ 0	37,861	0	0	37,861
Payments of tax withholdings related to vesting of employee stock awards and exercise of employee stock options	$ 0	(15,337)	0	0	(15,337)
Payments of tax withholdings related to vesting of employee stock awards and exercise of employee stock options (in shares)	(251)
Balance at Mar. 31, 2021	$ 141	1,925,801	(24,203)	(1,221,175)	680,564
Balance (in shares) at Mar. 31, 2021	140,924
Balance at Dec. 31, 2021	$ 141	1,964,167	(32,668)	(1,159,903)	771,737
Balance (in shares) at Dec. 31, 2021	141,210
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	$ 0	0	0	(65,165)	(65,165)
Change in unrealized losses, net of tax	0	0	(15,756)	0	(15,756)
Foreign currency translation	0	0	(154)	0	(154)
Issuance of common stock in connection with employee stock plans	$ 1	1,848	0	0	1,849
Issuance of common stock in connection with employee stock plans (in shares)	847
Stock-based compensation expense	$ 0	26,236	0	0	26,236
Payments of tax withholdings related to vesting of employee stock awards and exercise of employee stock options	$ 0	(9,173)	0	0	(9,173)
Payments of tax withholdings related to vesting of employee stock awards and exercise of employee stock options (in shares)	(304)
Balance at Mar. 31, 2022	$ 142	$ 1,983,078	$ (48,578)	$ (1,225,068)	$ 709,574
Balance (in shares) at Mar. 31, 2022	141,753