Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Statement of Comprehensive Income [Abstract]
Revenue		$ 15	$ 34	$ 30	$ 50
Operating expenses:
Research and development		28,172	39,500	106,476	122,935
General and administrative		10,687	11,769	34,519	37,519
Other operating income, net		(1,591)	(730)	(648)	(2,796)
Impairment of long-lived assets		0	0	1,443	0
Total operating expenses		37,268	50,539	141,790	157,658
Loss from operations		(37,253)	(50,505)	(141,760)	(157,608)
Interest income, net		3,266	5,965	10,404	19,148
Other (expense) income, net		(4,859)	(43)	(2,369)	402
Impairment of other investments		0	0	0	(13,001)
Total other (loss) income, net		(1,593)	5,922	8,035	6,549
Net loss		(38,846)	(44,583)	(133,725)	(151,059)
Other comprehensive loss:
Net unrealized gain (loss) on marketable securities		144	1,157	(90)	854
Comprehensive loss		$ (38,702)	$ (43,426)	$ (133,815)	$ (150,205)
Net loss per common share, basic (in dollars per share)	[1]	$ (2.13)	$ (3.48)	$ (8.38)	$ (11.83)
Net loss per common share, diluted (in dollars per share)	[1]	$ (2.13)	$ (3.48)	$ (8.38)	$ (11.83)
Weighted-average shares used to compute net loss per common share, basic (in shares)	[1]	18,268	12,815	15,952	12,766
Weighted-average shares used to compute net loss per common share, diluted (in shares)	[1]	18,268	12,815	15,952	12,766

[1] Amounts previously reported have been retroactively adjusted to reflect the 1-for-20 reverse stock split effected on May 30, 2025. See Note 2.