Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Statement [Abstract]
Collaboration revenue	$ 9,326	$ 6,787	$ 2,319
Revenue from Contract with Customer, Product and Service [Extensible Enumeration]	us-gaap:LicenseAndServiceMember	us-gaap:LicenseAndServiceMember	us-gaap:LicenseAndServiceMember
Operating expenses:
Research and development	$ 101,182	$ 37,602	$ 14,539
General and administrative	26,195	13,462	5,112
Total operating expenses	127,377	51,064	19,651
Loss from operations	(118,051)	(44,277)	(17,332)
Other income (expense):
Interest income	104	206	0
Interest expense	0	(209)	(7,387)
Change in fair value of preferred warrant liability	0	(75)	(15)
Other expense	(62)	0	0
Total other income (expense)	42	(78)	(7,402)
Net loss	(118,009)	(44,355)	(24,734)
Other comprehensive income (loss):
Net unrealized losses on marketable securities	(182)	(5)	0
Comprehensive loss	$ (118,191)	$ (44,360)	$ (24,734)
Net loss per share/unit, basic and diluted	$ (2.85)	$ (2.05)	$ (9.12)
Weighted-average shares/units outstanding, basic and diluted	41,428	21,663	2,713