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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 |
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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 |  |  |  |  |  |  |  |  |

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