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Collaborations - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands				1 Months Ended	3 Months Ended				9 Months Ended		12 Months Ended
	Jun. 25, 2025	Jul. 07, 2020	May 09, 2019	Jun. 30, 2025	Sep. 30, 2025	Jun. 30, 2025	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024	Dec. 31, 2023
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Cost reimbursement payment received									$ 900
Research and development					$ 74,094		$ 60,410		232,737	$ 168,431
Revenue					2,764		3,741		36,341	39,678
Revenue Recognized									75,000
Milestone Two [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Revenue recognized recorded in deferred revenue					0				23,600
Unconstrained Consideration												$ 55,000
Collaboration Target 1
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaboration revenue recognised									11,500
Gilead Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront payment	$ 40,000
Option exercise payment	45,000
Collaboration agreement transaction price									40,000
Revenue recognized recorded in deferred revenue									$ 37,200		$ 0
Remaining research term of collaboration									1 year 6 months
Revenue					2,800				$ 2,800
Deferred Revenue					37,200				37,200
Increase in Revenue						$ 40,000
Gilead Agreement \| Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Development milestone payments	665,000
Commercial Milestone Payments	$ 665,000
Sanofi Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Upfront payment		$ 150,000
Collaboration agreement transaction price		150,000
Revenue recognized recorded in deferred revenue									33,600		13,600
Unsatisfied performance obligation					0				0		13,600
Unconstrained Consideration					20,000				20,000
Sanofi Agreement \| Milestone One [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaboration revenue recognised								$ 40,000
Sanofi Agreement \| Milestone Two [Member]
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaboration revenue recognised								$ 15,000
Sanofi Agreement \| Collaboration Target 1
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaboration agreement transaction price		120,000
Revenue recognized recorded in deferred revenue					0				33,600	$ 39,700
Revenue							$ 3,700
Sanofi Agreement \| Collaboration Target 2
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaboration agreement transaction price		30,000
Sanofi Agreement \| Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Development milestone payments		1,480,000		$ 975,000
Commercial Milestone Payments		$ 700,000		$ 975,000
Vertex Agreement
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Unsatisfied performance obligation					$ 0				$ 0		$ 0
Initial research term of collaboration			4 years
Extended research term of collaboration			1 year
Vertex Agreement \| Series B-1 Preferred Stock
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaboration agreement transaction price			$ 55,900
Non refundable upfront payment received			$ 50,000
Stock Issued During Period, Shares, New Issues			3,059,695
Stock issued price per share			$ 6.54
Preferred stock premium			$ 5,900
Vertex Agreement \| Maximum
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Eligible to receive payments including development, regulatory and commercial milestones			$ 170,000