Segment Information - Summary of Significant Segment Expenses (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2026	Jun. 30, 2026	Mar. 31, 2026	Sep. 30, 2025	Jun. 30, 2025	Mar. 31, 2025	Sep. 30, 2026	Sep. 30, 2025
Operating Expenses [Abstract]
Employee-related expenses, excluding stock-based compensation	$ 4,296			$ 3,419			$ 12,317	$ 10,333
Stock-based compensation	178			129			522	312
External research and development expenses	6,556			3,048			23,606	10,490
External general and administrative expenses	732			491			2,481	1,848
Other segment expenses	2,154			1,626			6,008	4,954
Total operating expenses	13,916			8,713			44,934	27,937
Loss from operations	(13,916)			(8,713)			(44,934)	(27,937)
Interest income	768			853			2,523	2,421
Other expense, net	(3)			0			(6)	(66)
Total other income, net	765			853			2,517	2,355
Loss before provision for income taxes	(13,151)			(7,860)			(42,417)	(25,582)
Provision for income taxes	88			0			130	0
Net loss	$ (13,239)	$ (13,085)	$ (16,223)	$ (7,860)	$ (8,328)	$ (9,394)	$ (42,547)	$ (25,582)