Leases - Assets and Liabilities - Finance Leases (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Sep. 30, 2021
Finance Lease, Right-of-Use Asset, after Accumulated Amortization [Abstract]
Property, plant and equipment, at cost	$ 2,252	$ 2,252
Accumulated amortization	(2,234)	(2,105)
Property, plant and equipment, net	$ 18	$ 147
Finance Lease, Right-of-Use Asset, Statement of Financial Position	Property, plant and equipment, net	Property, plant and equipment, net
Finance Lease Liability [Abstract]
Accrued expenses and other current liabilities	$ 44	$ 360
Finance Lease, Liability, Current, Statement of Financial Position	Accrued expenses and other current liabilities	Accrued expenses and other current liabilities
Other long-term liabilities, net	$ (10)	$ (10)
Total finance lease liabilities	$ 34	$ 350