Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Income Statement [Abstract]
Revenue from collaboration agreements	$ 15,362,000	$ 11,072,000	$ 30,407,000	$ 17,495,000
Operating expenses:
Research and development	31,838,000	28,347,000	78,124,000	87,315,000
General and administrative	11,768,000	10,533,000	31,751,000	31,784,000
Restructuring	0	0	2,437,000	0
Total operating expenses	43,606,000	38,880,000	112,312,000	119,099,000
Loss from operations	(28,244,000)	(27,808,000)	(81,905,000)	(101,604,000)
Other income (expense), net:
Interest expense and amortization of long-term debt − related party	0	(167,000)	0	(1,373,000)
Loss on early extinguishment of debt	0	(621,000)	0	(621,000)
Interest and other income, net	3,578,000	2,562,000	11,162,000	6,862,000
Total other income, net	3,578,000	1,774,000	11,162,000	4,868,000
Loss before income taxes	(24,666,000)	(26,034,000)	(70,743,000)	(96,736,000)
Income tax expense	0	(1,003,000)	0	(1,003,000)
Net loss	$ (24,666,000)	$ (27,037,000)	$ (70,743,000)	$ (97,739,000)
Net loss per share − basic (in dollars per share)	$ (0.35)	$ (0.55)	$ (1.03)	$ (1.99)
Net loss per share − diluted (in dollars per share)	$ (0.35)	$ (0.55)	$ (1.03)	$ (1.99)
Weighted-average number of shares used in computed net loss per share − basic	69,627,190	49,212,126	68,958,938	49,103,351
Weighted-average number of shares used in computed net loss per share − diluted	69,627,190	49,212,126	68,958,938	49,103,351
Other comprehensive income (loss)
Unrealized gain on marketable securities	$ 895,000	$ 870,000	$ 582,000	$ 3,233,000
Comprehensive loss	$ (23,771,000)	$ (26,167,000)	$ (70,161,000)	$ (94,506,000)
Revenue from Contract with Customer, Product and Service [Extensible Enumeration]			Collaborative Arrangement [Member]	Collaborative Arrangement [Member]