Consolidated Statements of Changes in Stockholders' Equity (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Stockholders' Equity Attributable to Parent	$ 176,962	$ 306,948	$ 104,151
Common stock issued for stock options and restricted stock units	6,453	18,751	18,387
Tax withholdings related to net share settlements of restricted stock units	(2,585)	(2,012)	(1,474)
Common stock issued for employee stock purchase plan	2,428	2,190	1,952
Stock-based compensation	30,385	18,963	17,458
Other comprehensive loss	(401)	(62)	185
Net loss	(115,254)	(110,078)	(40,696)
Cumulative Effect, Period of Adoption, Adjustment
Stockholders' Equity Attributable to Parent		(51,012)
Additional Paid-in Capital
Issuance cost	14,200		4,700
Stockholders' Equity Attributable to Parent	827,028	848,891	535,954
Common stock issued for stock options and restricted stock units	6,452	18,751	18,387
Tax withholdings related to net share settlements of restricted stock units	(2,585)	(2,012)	(1,474)
Common stock issued for employee stock purchase plan	2,428	2,190	1,952
Stock-based compensation	$ 30,385	18,963	$ 17,458
Additional Paid-in Capital | Cumulative Effect, Period of Adoption, Adjustment
Stockholders' Equity Attributable to Parent		$ (58,543)
Common Stock
Shares, Outstanding	45,729	44,441	36,298
Stockholders' Equity Attributable to Parent	$ 5	$ 4	$ 4
Common stock issued for stock options and restricted stock units	$ 1
Issuance of common stock for employee stock purchase plan (in shares)	65	89	203
Shares Issued, Shares, Share-based Payment Arrangement, after Forfeiture	1,223	1,890	2,007
Accumulated Other Comprehensive Income (Loss)
Stockholders' Equity Attributable to Parent	$ (318)	$ 83	$ 145
Other comprehensive loss	(401)	(62)	185
Accumulated Deficit
Stockholders' Equity Attributable to Parent	(649,753)	(542,030)	(431,952)
Net loss	$ (115,254)	(110,078)	$ (40,696)
Accumulated Deficit | Cumulative Effect, Period of Adoption, Adjustment
Stockholders' Equity Attributable to Parent		$ 7,531