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License Agreements - Expenses Related Development Costs (Details) - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended
--- | --- | ---
Dec. 31, 2024 | Dec. 31, 2025
Research and Development Arrangement, Contract to Perform for Others [Line Items] |  |  |
Research and development expense | [1] | $ 14,034 | $ 138,086
General and administrative expense | [2] | 3,157 | 25,390
Paragon Therapeutics | License Agreement Terms | Paragon Option Agreements |  |  |
Research and Development Arrangement, Contract to Perform for Others [Line Items] |  |  |
Research and development expense |  | 13,124 | 19,356
General and administrative expense |  | 394 | 570
Operating costs and expenses, total |  | $ 13,518 | $ 19,926
[1] | Includes related party amount of $23,653 for the twelve months ended months ended December 31, 2025 and $13,185 for the period from September 19, 2024 (inception) through December 31, 2024.
[2] | Includes related party amount of $720 for the twelve months ended months ended December 31, 2025 and $571 for the period from September 19, 2024 (inception) through December 31, 2024.

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