Liability Related to the Sale of Future Royalties - Schedule of Liability Related to the Sale of Future Royalties (Details) - USD ($) $ in Thousands |
9 Months Ended | |
|---|---|---|
Jun. 30, 2026 |
Jun. 30, 2025 |
|
| Liability, Sale Of Future Royalties [Roll Forward] | ||
| Beginning carrying value | $ 367,397 | $ 341,361 |
| Non-cash interest expense recognized | 25,115 | 18,893 |
| Ending carrying value | $ 392,512 | $ 360,254 |