Segment Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2024 USD ($) segment	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Segment Information
Number of reportable segment | segment	1
Collaboration revenue	$ 80,001	$ 250,008	$ 40,907
General and administrative	35,920	35,822	30,980
Interest income	18,328	11,721	1,792
Other income	622	3	2,653
Income tax provision	665	1,408	16
Net Income (Loss)	(65,002)	132,330	(46,408)
Single reportable segment
Segment Information
Collaboration revenue	80,001	250,008	40,907
Internal research and development	38,422	27,860	20,505
Facilities and other research and development	30,865	18,304	18,037
General and administrative	35,920	35,822	30,980
Interest income	18,328	11,721	1,792
Other income	622	3	2,653
Income tax provision	665	1,408	16
Net Income (Loss)	(65,002)	132,330	(46,408)
Single reportable segment | Anti-tau antibody program
Segment Information
External research and development	15,647	16,923	1,190
Single reportable segment | SOD1 silencing gene therapy program
Segment Information
External research and development	15,818	6,251	3,082
Single reportable segment | Tau silencing gene therapy program
Segment Information
External research and development	7,455	696
Single reportable segment | Partnered programs
Segment Information
External research and development	4,985	7,650	3,229
Single reportable segment | Other programs and platforms
Segment Information
External research and development	$ 14,176	$ 14,488	$ 14,721