Balance Sheet Accounts - Accrued Expenses (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Sep. 30, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accrued R&D expenses	$ 28,069	$ 12,826
Accrued R&D expenses; co-development	23,351	5,895
Accrued capital expenditures	4,206	14,044
Other	7,391	6,998
Total accrued expenses	$ 63,017	$ 39,763