CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Accumulated Other Comprehensive (Loss) Income
Beginning balance (in shares) at Dec. 31, 2020		91,502,461
Beginning balance at Dec. 31, 2020	$ 130,670	$ 915	$ 1,176,647	$ (1,046,889)	$ (3)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Recognition of stock-based compensation	1,099		1,099
Exercise of stock options (in shares)		31,811
Exercise of stock options	79	$ 1	78
Unrealized gain (loss) on marketable securities	(6)				(6)
Net loss	(9,927)			(9,927)
Ending balance (in shares) at Mar. 31, 2021		91,534,272
Ending balance at Mar. 31, 2021	121,915	$ 916	1,177,824	(1,056,816)	(9)
Beginning balance (in shares) at Dec. 31, 2020		91,502,461
Beginning balance at Dec. 31, 2020	130,670	$ 915	1,176,647	(1,046,889)	(3)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(20,765)
Ending balance (in shares) at Jun. 30, 2021		91,596,369
Ending balance at Jun. 30, 2021	112,474	$ 916	1,179,215	(1,067,654)	(3)
Beginning balance (in shares) at Mar. 31, 2021		91,534,272
Beginning balance at Mar. 31, 2021	121,915	$ 916	1,177,824	(1,056,816)	(9)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Recognition of stock-based compensation	1,275		1,275
Issuance of stock under Employee Stock Purchase Plan (in shares)		20,791
Issuance of stock under Employee Stock Purchase Plan	68		68
Exercise of stock options (in shares)		41,306
Exercise of stock options	48		48
Unrealized gain (loss) on marketable securities	6				6
Net loss	(10,838)			(10,838)
Ending balance (in shares) at Jun. 30, 2021		91,596,369
Ending balance at Jun. 30, 2021	$ 112,474	$ 916	1,179,215	(1,067,654)	(3)
Beginning balance (in shares) at Dec. 31, 2021	91,645,369	91,645,369
Beginning balance at Dec. 31, 2021	$ 90,707	$ 916	1,182,225	(1,092,325)	(109)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Recognition of stock-based compensation	1,718		1,718
Unrealized gain (loss) on marketable securities	(342)				(342)
Net loss	(16,109)			(16,109)
Ending balance (in shares) at Mar. 31, 2022		91,645,369
Ending balance at Mar. 31, 2022	$ 75,974	$ 916	1,183,943	(1,108,434)	(451)
Beginning balance (in shares) at Dec. 31, 2021	91,645,369	91,645,369
Beginning balance at Dec. 31, 2021	$ 90,707	$ 916	1,182,225	(1,092,325)	(109)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options (in shares)	0
Net loss	$ (32,049)
Ending balance (in shares) at Jun. 30, 2022	91,814,665	91,814,665
Ending balance at Jun. 30, 2022	$ 62,045	$ 918	1,186,056	(1,124,374)	(555)
Beginning balance (in shares) at Mar. 31, 2022		91,645,369
Beginning balance at Mar. 31, 2022	75,974	$ 916	1,183,943	(1,108,434)	(451)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Recognition of stock-based compensation	1,966		1,966
Issuance of stock under Employee Stock Purchase Plan (in shares)		169,296
Issuance of stock under Employee Stock Purchase Plan	149	$ 2	147
Unrealized gain (loss) on marketable securities	(104)				(104)
Net loss	$ (15,940)			(15,940)
Ending balance (in shares) at Jun. 30, 2022	91,814,665	91,814,665
Ending balance at Jun. 30, 2022	$ 62,045	$ 918	$ 1,186,056	$ (1,124,374)	$ (555)