Collaboration and License Agreements - Schedule of Deferred Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Sep. 30, 2025
Movement In Contract With Customer Liability [Roll Forward]
Balance at beginning of period	$ 2,399	$ 0
Deferred revenue additions	417,238	0
Revenue recognized	(263,706)	0
Balance at end of period	155,931	0
Plus contract assets included in other current assets	9,827	0	$ 0
Less deferred revenue, current	(111,933)	0	(2,399)
Deferred revenue, non-current	$ 53,825	$ 0	$ 0