Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Sep. 30, 2022
Deferred tax assets:
Federal and state net operating loss and tax credit carryforwards	$ 138,856	$ 149,299
Incentive compensation	11,422	12,914
Warranty and other reserves	6,918	7,091
Inventory adjustments	3,942	6,716
Intangible assets	0	1,515
Property, equipment and other assets	1,276	771
Uncertain tax positions	705	705
Other	2,504	2,743
Total deferred tax assets	165,623	181,754
Valuation allowance	(30,438)	(25,396)
Total deferred tax assets, net of valuation allowance	135,185	156,358
Intangible assets	(1,236)	0
Total deferred tax liabilities	(1,236)	0
Net deferred tax assets	$ 133,949	$ 156,358