Collaboration Agreements - Takeda (Details)			12 Months Ended			50 Months Ended
		Feb. 23, 2018 USD ($) shares	Dec. 31, 2025 USD ($)	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2025 USD ($)	Dec. 31, 2022 USD ($) program	Dec. 31, 2021 program	Nov. 30, 2021 USD ($)
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaborative revenue, revenue from contract with customer	[1]		$ 0	$ 0	$ 330,531,000
Performance obligation				$ 0
Takeda Pharmaceutical Company Limited | Collaborative Arrangement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront payment		$ 40,000,000.0
Possible preclinical milestone payments (up to)							$ 55,000,000.0
Number of performance obligations under the programs | program							3
Performance obligation			0			$ 0
Number of performance obligations suspended | program								2
Takeda Pharmaceutical Company Limited | Collaborative Arrangement | Share Purchase Agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Number of common stock (in shares) | shares		4,214,559
Net proceeds		$ 110,000,000.0
Takeda Pharmaceutical Company Limited | Collaborative Arrangement | Product
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaborative revenue, revenue from contract with customer			$ 0
Takeda Pharmaceutical Company Limited | Collaborative Arrangement, PTV:PGRN And ATV:TREM2
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Option fee									$ 5,000,000.0
Takeda Pharmaceutical Company Limited | Collaborative Arrangement, PTV:PGRN And ATV:TREM2 | Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Milestone payments per biologic product upon achievement of a certain sales-based milestone									75,000,000.0
Takeda Pharmaceutical Company Limited | Collaborative Arrangement, PTV:PGRN | Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Total aggregate payments due upon achievement of certain clinical milestone events									140,000,000.0
Regulatory milestone payment									$ 100,000,000.0
Takeda Pharmaceutical Company Limited | Collaborative Arrangement, PTV:PGRN | Product
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaborative revenue, revenue from contract with customer						$ 0
Takeda Pharmaceutical Company Limited | Collaborative Arrangement, PTV:PGRN | Milestone Triggered
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Clinical milestone payment					$ 10,000,000.0

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