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Collaboration Agreements, License Agreement and Revenues - Astellas Agreements - Additional Information (Detail) - USD ($) | 1 Months Ended | 3 Months Ended | 6 Months Ended | 9 Months Ended |
--- | --- | --- | --- | --- | ---
Apr. 30, 2006 | Jun. 30, 2005 | Sep. 30, 2025 | Sep. 30, 2024 | Jun. 30, 2025 | Sep. 30, 2025 | Sep. 30, 2024 | Dec. 31, 2024
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items] |  |  |  |  |  |  |  |
Total revenue |  |  | $ 1,076,000 | $ 123,000 |  | $ 5,163,000 | $ 26,486,000 |
Deferred Revenue |  |  | 5,104,000 |  |  | 5,104,000 |  | $ 27,290,000
Drug Product Revenue, Net [Member] |  |  |  |  |  |  |  |
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items] |  |  |  |  |  |  |  |
Total revenue |  |  | 957,000 | (262,000) |  | 4,767,000 | 24,954,000 |
Japan [Member] |  |  |  |  |  |  |  |
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items] |  |  |  |  |  |  |  |
Transaction price, variable consideration from estimated future co-development billing |  |  |  |  |  | 0 |  |
Europe [Member] |  |  |  |  |  |  |  |
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items] |  |  |  |  |  |  |  |
Transaction price, variable consideration from estimated future co-development billing |  |  |  |  |  | $ 0 |  |
Astellas Agreement [Member] | Japan [Member] |  |  |  |  |  |  |  |
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items] |  |  |  |  |  |  |  |
Upfront, non-contingent and time-based payments received |  | $ 172,600,000 |  |  |  |  |  |
Additional consideration based on net sales description |  |  |  |  |  | the low 20% range of the list price |  |
Aggregate consideration received excluding drug product revenue |  |  | 105,100,000 |  |  | $ 105,100,000 |  |
Transaction price, variable consideration from estimated future co-development billing |  |  | 0 | 0 |  | 0 | 0 |
Changes in revenue from changes to estimated variable consideration |  |  |  |  |  | 0 |  |
Astellas Agreement [Member] | Japan [Member] | License [Member] |  |  |  |  |  |  |  |
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items] |  |  |  |  |  |  |  |
Cash Consideration Received Under Collaboration Agreement |  |  | 100,300,000 |  |  | 100,300,000 |  |
Astellas Agreement [Member] | Japan [Member] | Co-development, information sharing & committee services [Member] |  |  |  |  |  |  |  |
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items] |  |  |  |  |  |  |  |
Cash Consideration Received Under Collaboration Agreement |  |  | 17,100,000 |  |  | 17,100,000 |  |
Astellas Agreement [Member] | Europe [Member] |  |  |  |  |  |  |  |
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items] |  |  |  |  |  |  |  |
Upfront, non-contingent and time-based payments received | $ 745,000,000 |  |  |  |  |  |  |
Additional consideration based on net sales description |  |  |  |  | low 20% range |  |  |
Aggregate consideration received excluding drug product revenue |  |  | 685,000,000 |  |  | 685,000,000 |  |
Percentage of joint development costs committed to fund | 50.00% |  |  |  |  |  |  |
Changes in revenue from changes to estimated variable consideration |  |  | 0 |  |  |  |  |
Astellas Agreement [Member] | Europe [Member] | License [Member] |  |  |  |  |  |  |  |
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items] |  |  |  |  |  |  |  |
Total revenue |  |  | 0 | $ 0 |  | 0 | $ 0 |
Cash Consideration Received Under Collaboration Agreement |  |  | 619,000,000 |  |  | 619,000,000 |  |
Astellas Agreement [Member] | Europe [Member] | Co-development, information sharing & committee services [Member] |  |  |  |  |  |  |  |
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items] |  |  |  |  |  |  |  |
Cash Consideration Received Under Collaboration Agreement |  |  | $ 288,500,000 |  |  | $ 288,500,000 |  |

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