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Collaborative and Other Relationships - Summary of Activity Related to Sage Therapeutics (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Sep. 30, 2024 | Sep. 30, 2023 | Sep. 30, 2024 | Sep. 30, 2023 | Dec. 31, 2024
Collaborative arrangements and non-collaborative arrangement transactions |  |  |  |  |
Share of net profit from sage therapeutics, Percent | 50.00% |  | 50.00% |  |
Collaboration profit sharing/(loss reimbursement) | $ 69.3 | $ 50.5 | $ 197.3 | $ 164.5 |
Sage Therapeutics |  |  |  |  |
Collaborative arrangements and non-collaborative arrangement transactions |  |  |  |  |
Collaboration profit sharing/(loss reimbursement) | 9.0 | 5.9 | 20.5 | 5.9 |
Sage Therapeutics | Forecast |  |  |  |  |
Collaborative arrangements and non-collaborative arrangement transactions |  |  |  |  |
Potential future milestone payments commitment to third party |  |  |  |  | $ 75.0
Research and development | Sage Therapeutics |  |  |  |  |
Collaborative arrangements and non-collaborative arrangement transactions |  |  |  |  |
Expense incurred by the collaboration | 8.4 | 72.0 | 29.6 | 158.9 |
Expense reflected within statements of income | 4.2 | 36.0 | 14.8 | 79.5 |
Selling, general and administrative | Sage Therapeutics |  |  |  |  |
Collaborative arrangements and non-collaborative arrangement transactions |  |  |  |  |
Expense incurred by the collaboration | 28.4 | 54.0 | 82.9 | 152.3 |
Expense reflected within statements of income | $ 14.2 | $ 27.0 | $ 41.5 | $ 76.1 |

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