CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Income Statement [Abstract]
Collaboration Revenue—from related parties	$ 4,728	$ 9,551	$ 30,707	$ 30,687
Revenue from Contract with Customer, Product and Service [Extensible Enumeration]	us-gaap:RelatedPartyMember	us-gaap:RelatedPartyMember	us-gaap:RelatedPartyMember	us-gaap:RelatedPartyMember
Operating expenses:
Research and development	$ 48,117	$ 43,877	$ 136,111	$ 121,115
General and administrative	14,120	10,556	40,814	32,198
Total operating expenses	62,237	54,433	176,925	153,313
Loss from operations	(57,509)	(44,882)	(146,218)	(122,626)
Other income (expense):
Interest and other Income	4,683	1,916	13,768	2,800
Interest and other expense	(41)	(36)	(144)	(117)
Total other income:	4,642	1,880	13,624	2,683
Net loss	(52,867)	(43,002)	(132,594)	(119,943)
Other comprehensive loss:
Unrealized (loss) gain on marketable securities	1,185	(1,930)	2,499	(5,253)
Total comprehensive loss	(51,682)	(44,932)	(130,095)	(125,196)
Net loss	$ (52,867)	$ (43,002)	$ (132,594)	$ (119,943)
Net loss per share, basic and diluted	$ (0.9)	$ (0.79)	$ (2.27)	$ (2.28)
Net loss per share, basic and diluted	$ (0.9)	$ (0.79)	$ (2.27)	$ (2.28)
Weighted average common shares outstanding, basic and diluted	58,421,859	54,535,514	58,312,813	52,600,103
Weighted average common shares outstanding, basic and diluted	58,421,859	54,535,514	58,312,813	52,600,103