Leases - Components of lease costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Operating Lease:
Total lease costs	$ 662	$ 756
Total lease costs, net of sublease interest income	659	755
Interest expense
Finance Lease:
Interest on lease liabilities	1	4
Selling, general and administrative
Operating Lease:
Operating lease cost	618	615
Short-term lease cost	43	137
Revenue.
Operating Lease:
Less sublease interest income	$ (3)	$ (1)