Income Taxes - Provisions for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Current:
Federal	$ 1,074	$ 0	$ 0
State	1,710	304	2
Foreign	0	3,481	0
Total current tax	2,784	3,785	2
Deferred:
Federal	0	0	0
State	0	0	0
Foreign	0	0	0
Total deferred tax	0	0	0
Income tax provision	$ 2,784	$ 3,785	$ 2