Condensed Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Income Statement [Abstract]
Collaboration revenue	$ 2,178	$ 2,607	$ 3,973	$ 5,311
Revenue from Contract with Customer, Product and Service [Extensible Enumeration]	us-gaap:LicenseAndServiceMember	us-gaap:LicenseAndServiceMember	us-gaap:LicenseAndServiceMember	us-gaap:LicenseAndServiceMember
Operating expenses:
Research and development	$ 39,789	$ 22,706	$ 67,477	$ 43,383
General and administrative	8,688	6,268	17,255	12,152
Total operating expenses	48,477	28,974	84,732	55,535
Loss from operations	(46,299)	(26,367)	(80,759)	(50,224)
Other income (expense):
Interest income	611	16	861	32
Other expense	(2)	(2)	(27)	(5)
Total other income	609	14	834	27
Net loss	(45,690)	(26,353)	(79,925)	(50,197)
Other comprehensive income (loss):
Net unrealized (losses) gains on marketable securities	(960)	3	(2,799)	5
Comprehensive loss	$ (46,650)	$ (26,350)	$ (82,724)	$ (50,192)
Net loss per share, basic	$ (0.92)	$ (0.70)	$ (1.63)	$ (1.34)
Net loss per share, diluted	$ (0.92)	$ (0.70)	$ (1.63)	$ (1.34)
Weighted-average shares outstanding, basic	49,927	37,583	49,091	37,552
Weighted-average shares outstanding, diluted	49,927	37,583	49,091	37,552