Liability Related to the Sale of Future Royalties - Schedule of Liability Related to the Sale of Future Royalties (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2025	Dec. 31, 2024
Liability, Sale Of Future Royalties [Roll Forward]
Beginning carrying value	$ 367,397	$ 341,361
Milestone payment received	0	0
Non-cash interest expense recognized	7,600	5,415
Ending carrying value	$ 374,997	$ 346,776