Collaboration Agreements - Biogen (Details)		1 Months Ended		12 Months Ended			65 Months Ended
		Oct. 31, 2020 USD ($)	Sep. 30, 2020 USD ($) shares	Dec. 31, 2025 USD ($)	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2025 USD ($)	Aug. 31, 2020 USD ($) program
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaborative revenue, revenue from contract with customer	[1]			$ 0	$ 0	$ 330,531,000
LRRK2 Agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Funded percentage								40.00%
LRRK2 Agreement | Biogen
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Funded percentage								60.00%
Biogen | Provisional Collaboration Agreement | Share Purchase Agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Number of common stock (in shares) | shares			13,310,243
Net proceeds			$ 465,000,000.0
Biogen | Biogen Collaboration Agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront payment		$ 560,000,000.0
Biogen | LRRK2 Agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone payments upon achievement of certain development, first commercial sale, and net sales based milestones								$ 1,125,000,000
Development milestone payments								375,000,000.0
First commercial sale milestone payments								375,000,000.0
Net sales-based milestone payments								$ 375,000,000.0
Biogen | LRRK2 Agreement | United States
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Agreed share of commercial profit (loss) percentage								50.00%
Biogen | LRRK2 Agreement | China
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Agreed share of commercial profit (loss) percentage								40.00%
Biogen | Transport Vehicle (TV) Technology Platform, Unnamed Program | Provisional Collaboration Agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Number of programs | program								1
Biogen | Transport Vehicle Technology Platform, Right Of First Negotiation Programs | Provisional Collaboration Agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Number of additional programs, if circumstances met | program								2
Biogen | Option Fee Payment | Biogen Collaboration Agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaborative revenue, revenue from contract with customer							$ 5,000,000.0
Biogen | Product | Biogen Collaboration Agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaborative revenue, revenue from contract with customer							$ 0

[1] Includes related-party collaboration revenue from customers of $295.5 million for the year ended December 31, 2023.