Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Statement [Abstract]
Collaboration revenue	$ 36,855	$ 26,581	$ 43
Operating expenses:
Research and development	148,269	173,385	132,013
General and administrative	59,543	56,963	36,888
Restructuring expenses	8,713	0	0
Total operating expenses	216,525	230,348	168,901
Other income (expense):
Interest income	12,073	2,883	65
Interest expense	(4,073)	(3,328)	(1,267)
Total other income (expense), net	8,000	(445)	(1,202)
Net loss	(171,670)	(204,212)	(170,060)
Other comprehensive loss:
Unrealized gain (loss) on marketable securities	163	(152)	0
Comprehensive loss	(171,507)	(204,364)	(170,060)
Net loss attributable to common stockholders - basic	(171,670)	(204,212)	(170,060)
Net loss attributable to common stockholders - diluted	$ (171,670)	$ (204,212)	$ (170,060)
Net loss per share attributable to common stockholders — basic (in dollars per share)	$ (1.48)	$ (2.18)	$ (2.41)
Net loss per share attributable to common stockholders — diluted (in dollars per share)	$ (1.48)	$ (2.18)	$ (2.41)
Weighted-average number of shares of common stock used in net loss per share attributable to common stockholders — basic (in shares)	116,112,891	93,654,243	70,580,949
Weighted-average number of shares of common stock used in net loss per share attributable to common stockholders — diluted (in shares)	116,112,891	93,654,243	70,580,949