Segment Information - Segment and Geographic Area Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Segment Reporting [Abstract]
Revenue	$ 5,333	$ 9,477	$ 29,786	$ 21,161
DURAVYU direct research and development expense	(37,349)	(16,376)	(79,247)	(30,086)
Other direct research and development expense	(1,003)	(373)	(1,988)	(80)
Personnel expense (including stock based compensation)	(20,065)	(19,737)	(40,907)	(43,962)
Facilities expense	(1,863)	(909)	(3,267)	(1,537)
Depreciation and amortization	(538)	(362)	(1,035)	(665)
Intellectual property expense	(210)	(408)	(474)	(726)
Legal, corporate and professional expenses	(2,967)	(2,264)	(5,867)	(5,339)
Provision for income taxes	(93)	0	(93)	0
Interest and other income, net	2,894	3,720	6,536	7,757
Other segment expenses	(3,565)	(3,594)	(8,065)	(6,633)
Net loss	$ (59,426)	$ (30,826)	$ (104,621)	$ (60,110)