Stockholders' Equity (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Common Stock
Balance	$ 419,476	$ 209,357
Balance (in shares)	46,730,198
Shares issued under stock option and employee stock purchase plans	$ 304	74
Stock-based compensation	3,153	1,275
Unrealized loss on marketable securities	(1,782)	(2)
Net loss	(23,050)	(16,538)
Balance	$ 398,101	194,166
Balance (in shares)	46,754,348
Aggregate gross offering price available	$ 50,000
Common Stock
Common Stock
Balance	$ 47	$ 40
Balance (in shares)	46,730,198	39,603,771
Shares issued under stock option and employee stock purchase plans (in shares)	24,150	10,867
Balance	$ 47	$ 40
Balance (in shares)	46,754,348	39,614,638
Additional Paid-In Capital
Common Stock
Balance	$ 1,561,142	$ 1,279,824
Shares issued under stock option and employee stock purchase plans	304	74
Stock-based compensation	3,153	1,275
Balance	1,564,599	1,281,173
Accumulated Other Comprehensive Income.
Common Stock
Balance	1,894	2,589
Unrealized loss on marketable securities	(1,782)	(2)
Balance	112	2,587
Accumulated Deficit
Common Stock
Balance	(1,143,607)	(1,073,096)
Net loss	(23,050)	(16,538)
Balance	$ (1,166,657)	$ (1,089,634)