Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive (Loss) Income	Accumulated Deficit	Common Stock in Treasury	Non- controlling Interest
Common stock, beginning balance (in shares) at Sep. 30, 2022		105,960,000
Beginning balance at Sep. 30, 2022	$ 418,339	$ 198	$ 1,219,213	$ (136)	$ (820,755)		$ 19,819
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	78,130		78,130
Exercise of stock options (in shares)		439,000
Exercise of stock options	3,054	$ 1	3,053
Common stock - restricted stock units vesting (in shares)		913,000
Common stock - restricted stock units vesting	0	$ 1	(1)
Unrealized gains (losses) on available-for-sale securities	(2,964)			(2,964)
Foreign currency translation adjustments	(122)			(122)
Net (loss) income	(209,275)				(205,275)		(4,000)
Common stock, ending balance (in shares) at Sep. 30, 2023		107,312,000
Ending balance at Sep. 30, 2023	287,162	$ 200	1,300,395	(3,222)	(1,026,030)		15,819
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	73,968		73,968
Exercise of stock options (in shares)		226,000
Exercise of stock options	2,389		2,389
Common stock - restricted stock units vesting (in shares)		1,048,000
Common stock - restricted stock units vesting	0	$ 1	(1)
Common stock issued, net of offering costs (in shares)		15,790,000
Common stock issued	429,265	$ 16	429,249
Unrealized gains (losses) on available-for-sale securities	3,775			3,775
Foreign currency translation adjustments	4,197			4,197
Net (loss) income	$ (609,693)				(599,493)		(10,200)
Common stock, ending balance (in shares) at Sep. 30, 2024	124,376,000	124,376,000
Ending balance at Sep. 30, 2024	$ 191,063	$ 217	1,806,000	4,750	(1,625,523)	$ 0	5,619
Treasury stock, ending balance (in shares) at Sep. 30, 2024	0					0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	$ 63,366		63,366
Exercise of stock options (in shares)	535,140	535,000
Exercise of stock options	$ 3,983		3,983
Common stock - restricted stock units vesting (in shares)		1,526,000
Common stock - restricted stock units vesting	2	$ 2
Common stock issued, net of offering costs (in shares)		11,926,000
Common stock issued	241,388	$ 12	241,376
Common stock - repurchase (in shares)						(2,661,000)
Common stock - repurchase	(53,193)					$ (53,193)
Issuance of pre-funded warrants	25,000		25,000
Unrealized gains (losses) on available-for-sale securities	2,125			2,125
Foreign currency translation adjustments	(432)			(432)
Net (loss) income	$ 30,114				(1,631)		31,745
Common stock, ending balance (in shares) at Sep. 30, 2025	135,702,000	138,363,000
Ending balance at Sep. 30, 2025	$ 503,416	$ 231	$ 2,139,725	$ 6,443	$ (1,627,154)	$ (53,193)	$ 37,364
Treasury stock, ending balance (in shares) at Sep. 30, 2025	(2,661,000)					(2,661,000)