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Significant Accounting Policies - Estimated Fair Value of Assets and Liability (Detail) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands | Sep. 30, 2024 | Dec. 31, 2023
--- | --- | ---
Asset: |  |
Asset, fair value | $ 244,647 | $ 235,380
Money Market Fund |  |
Asset: |  |
Asset, fair value | 73,927 | 99,226
Agency Securities |  |
Asset: |  |
Asset, fair value |  | 8,912
Repo Securities |  |
Asset: |  |
Asset, fair value | 5,000 | 3,250
U.S. Treasury Securities |  |
Asset: |  |
Asset, fair value | 165,720 | 123,992
Level 1 |  |
Asset: |  |
Asset, fair value | 239,647 | 223,218
Level 1 | Money Market Fund |  |
Asset: |  |
Asset, fair value | 73,927 | 99,226
Level 1 | U.S. Treasury Securities |  |
Asset: |  |
Asset, fair value | 165,720 | 123,992
Level 2 |  |
Asset: |  |
Asset, fair value | 5,000 | 12,162
Level 2 | Agency Securities |  |
Asset: |  |
Asset, fair value |  | 8,912
Level 2 | Repo Securities |  |
Asset: |  |
Asset, fair value | $ 5,000 | $ 3,250

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