Leases - Additional Information (Detail) - USD ($)		12 Months Ended
	Aug. 28, 2020	Sep. 30, 2021	Sep. 30, 2020	Oct. 09, 2020
Lessee, Lease, Description [Line Items]
Total rental expense		$ 78,000	$ 37,000
Assets	$ 970,000
Operating Lease, Expense		440,000	28,000
Operating lease term	3 years
Operating leases paid in cash		468,000	0
New Lease Agreement [Member]
Lessee, Lease, Description [Line Items]
Assets				$ 254,000
Blaw Knox Product Line From Volvo CE [Member] | New Lease Agreement [Member]
Lessee, Lease, Description [Line Items]
Assets		$ 785,000	$ 942,000
Operating lease term				1 year
Operating lease liability date of expiry	Aug. 31, 2023