Income Taxes - Deferred tax assets (liabilities) (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Sep. 30, 2019
Deferred tax assets:
Pension	$ 1,410	$ 1,378
Intangibles	94	81
Other reserves and accruals	1,131	291
Inventory reserves and other	684	619
State credits, net of federal benefit	391	380
Federal and state net operating loss carryforwards	3	928
Foreign net operating loss carryforwards	1,766	1,393
Foreign exchange on intercompany loan		7
Depreciation and amortization	(244)	(232)
Gross deferred tax assets	5,235	4,845
Less: valuation allowance	(4,086)	(2,899)
Realizable deferred tax asset	1,149	1,946
Gross deferred tax liabilities	0	0
Net deferred tax assets	$ 1,149	$ 1,946