Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Sep. 30, 2023
Deferred tax assets:
Federal and state net operating loss and tax credit carryforwards	$ 126,547	$ 138,856
Incentive compensation	8,621	11,422
Warranty and other reserves	6,613	6,918
Inventory adjustments	7,914	3,942
Property, equipment and other assets	6,199	5,458
Uncertain tax positions	705	705
Other	4,816	2,504
Total deferred tax assets	161,415	169,805
Valuation allowance	(27,578)	(30,438)
Total deferred tax assets, net of valuation allowance	133,837	139,367
Operating lease right-of-use assets	(4,286)	(4,182)
Intangible assets	(1,026)	(1,236)
Total deferred tax liabilities	(5,312)	(5,418)
Net deferred tax assets	$ 128,525	$ 133,949