Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Statement [Abstract]
Collaboration revenue	$ 27,941	$ 19,538	$ 0
Operating expenses
Research and development	58,158	39,698	34,319
General and administrative	20,051	15,184	9,952
Total operating expenses	78,209	54,882	44,271
Loss from operations	(50,268)	(35,344)	(44,271)
Interest income and other income, net	506	849	2,296
Net loss	(49,762)	(34,495)	(41,975)
Unrealized (losses) gains on marketable securities	(719)	(58)	96
Comprehensive loss	$ (50,481)	$ (34,553)	$ (41,879)
Net loss per common share, basic and diluted	$ (1.41)	$ (1.40)	$ (3.36)
Weighted-average number of common shares outstanding used in computing net loss per share, basic and diluted	35,252,443	24,721,775	12,496,957