CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common Shares	Additional paid in capital	Accumulated Other Comprehensive (Loss) Income	Accumulated Deficit
Balance (in shares) at Dec. 31, 2021		141,600
Balance at Dec. 31, 2021	$ 479,091	$ 1,177,051	$ 59,014	$ (852)	$ (756,122)
Increase (Decrease) in Stockholders' Equity
Shares issued on exercise of stock options and vesting of performance awards and restricted stock units (in shares)		165
Shares issued on exercise of stock options and vesting of performance awards and restricted stock units	522	$ 1,928	(1,406)
Issuance of common shares in conjunction with ESPP program (in shares)		127
Issuance of common shares in conjunction with ESPP program	1,223	$ 1,905	(682)
Share-based compensation	17,078		17,078
Unrealized gain (loss) on available-for-sale securities, net	(1,001)			(1,001)
Net loss	(73,145)				(73,145)
Balance (in shares) at Jun. 30, 2022		141,892
Balance at Jun. 30, 2022	423,768	$ 1,180,884	74,004	(1,853)	(829,267)
Balance (in shares) at Mar. 31, 2022		141,742
Balance at Mar. 31, 2022	448,123	$ 1,178,807	64,686	(1,618)	(793,752)
Increase (Decrease) in Stockholders' Equity
Shares issued on exercise of stock options and vesting of performance awards and restricted stock units (in shares)		23
Shares issued on exercise of stock options and vesting of performance awards and restricted stock units	117	$ 172	(55)
Issuance of common shares in conjunction with ESPP program (in shares)		127
Issuance of common shares in conjunction with ESPP program	1,223	$ 1,905	(682)
Share-based compensation	10,055		10,055
Unrealized gain (loss) on available-for-sale securities, net	(235)			(235)
Net loss	(35,515)				(35,515)
Balance (in shares) at Jun. 30, 2022		141,892
Balance at Jun. 30, 2022	$ 423,768	$ 1,180,884	74,004	(1,853)	(829,267)
Balance (in shares) at Dec. 31, 2022	142,268	142,268
Balance at Dec. 31, 2022	$ 405,435	$ 1,185,309	85,489	(1,061)	(864,302)
Increase (Decrease) in Stockholders' Equity
Shares issued on exercise of stock options and vesting of performance awards and restricted stock units (in shares)	362	891
Shares issued on exercise of stock options and vesting of performance awards and restricted stock units	$ 1,873	$ 9,061	(7,188)
Issuance of common shares in conjunction with ESPP program (in shares)		210
Issuance of common shares in conjunction with ESPP program	906	$ 2,110	(1,204)
Share-based compensation	21,735		21,735
Unrealized gain (loss) on available-for-sale securities, net	41			41
Net loss	$ (37,698)				(37,698)
Balance (in shares) at Jun. 30, 2023	143,369	143,369
Balance at Jun. 30, 2023	$ 392,292	$ 1,196,480	98,832	(1,020)	(902,000)
Balance (in shares) at Mar. 31, 2023		143,029
Balance at Mar. 31, 2023	390,408	$ 1,193,019	88,885	(988)	(890,508)
Increase (Decrease) in Stockholders' Equity
Shares issued on exercise of stock options and vesting of performance awards and restricted stock units (in shares)		130
Shares issued on exercise of stock options and vesting of performance awards and restricted stock units	234	$ 1,351	(1,117)
Issuance of common shares in conjunction with ESPP program (in shares)		210
Issuance of common shares in conjunction with ESPP program	906	$ 2,110	(1,204)
Share-based compensation	12,268		12,268
Unrealized gain (loss) on available-for-sale securities, net	(32)			(32)
Net loss	$ (11,492)				(11,492)
Balance (in shares) at Jun. 30, 2023	143,369	143,369
Balance at Jun. 30, 2023	$ 392,292	$ 1,196,480	$ 98,832	$ (1,020)	$ (902,000)