Liability Related to the Sale of Future Royalties - Activity (Details) - USD ($) $ in Thousands	9 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Liability, Sale Of Future Royalties [Roll Forward]
Carrying value as of September 30, 2023	$ 268,326
Non-cash interest expense recognized	17,705	$ 13,064
Carrying value as of June 30, 2024	$ 336,031