Leases - Summary of Other Information Concerning the Company's Operating Lease (Detail) - USD ($)	Sep. 30, 2023	Sep. 30, 2022	Oct. 09, 2020	Sep. 30, 2020	Aug. 28, 2020
Lessee, Lease, Description [Line Items]
Current operating lease liability	$ 328,000	$ 390,000
Non-current operating lease liability	0	6,000
New Lease Agreement [Member]
Lessee, Lease, Description [Line Items]
Operating lease ROU asset included in other long-term assets	328,000	396,000	$ 254,000	$ 970,000	$ 352,000
Blaw Knox Product Line From Volvo CE [Member] | New Lease Agreement [Member]
Lessee, Lease, Description [Line Items]
Current operating lease liability	328,000	390,000
Non-current operating lease liability	$ 0	$ 6,000
Weighted average remaining lease term (in years)	6 months 3 days	1 year
Weighted average discount rate used in calculating ROU asset	4.50%	4.00%