Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit	Non- controlling Interest
Beginning balance at Sep. 30, 2020	$ 461,779	$ 195	$ 965,410	$ 18	$ (503,844)	$ 0
Beginning balance (in shares) at Sep. 30, 2020		102,376,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	76,673		76,673
Exercise of stock options	11,305	$ 1	11,304
Exercise of stock options (in shares)		1,052,000
Common stock - restricted stock units vesting	0	$ 1	(1)
Common stock - restricted stock units vesting (in shares)		899,000
Unrealized losses on available-for-sale securities	0
Foreign currency translation adjustments	(87)			(87)
Net loss	(140,848)				(140,848)
Ending balance at Sep. 30, 2021	408,822	$ 197	1,053,386	(69)	(644,692)	0
Ending balance (in shares) at Sep. 30, 2021		104,327,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	120,893		120,893
Exercise of stock options	5,185		5,185
Exercise of stock options (in shares)		606,000
Common stock - restricted stock units vesting	0	$ 1	(1)
Common stock - restricted stock units vesting (in shares)		1,027,000
Unrealized losses on available-for-sale securities	0
Foreign currency translation adjustments	(67)			(67)
Interest in joint venture	60,000		39,750			20,250
Net loss	(176,494)				(176,063)	(431)
Ending balance at Sep. 30, 2022	418,339	$ 198	1,219,213	(136)	(820,755)	19,819
Ending balance (in shares) at Sep. 30, 2022		105,960,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	78,130		78,130
Exercise of stock options	$ 3,054	$ 1	3,053
Exercise of stock options (in shares)	439,350	439,000
Common stock - restricted stock units vesting	$ 0	$ 1	(1)
Common stock - restricted stock units vesting (in shares)		913,000
Unrealized losses on available-for-sale securities	(2,964)			(2,964)
Foreign currency translation adjustments	(122)			(122)
Net loss	(209,275)				(205,275)	(4,000)
Ending balance at Sep. 30, 2023	$ 287,162	$ 200	$ 1,300,395	$ (3,222)	$ (1,026,030)	$ 15,819
Ending balance (in shares) at Sep. 30, 2023		107,312,000