Components of Net Deferred Income Tax Asset (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Sep. 30, 2019
Deferred income tax assets:
Allowance for doubtful accounts	$ 2,816	$ 192
Inventories	7,842	7,731
Loss and tax credit carry-forwards	22,027	22,377
Stock-based compensation	506	691
Accrued product warranty	54	47
Accrued compensated absences	328	313
Property and equipment	501	462
Prepaid income taxes	517	753
Other reserves	1,018	21
Deferred Tax Assets, Gross, Total	35,609	32,587
Deferred income tax liabilities:
Allowance for doubtful accounts	(11)
Intangible assets	(960)	(1,391)
Property, plant and equipment and other	(3,302)	(4,978)
Subtotal deferred income tax assets	31,336	26,218
Valuation allowance	(31,363)	(26,033)
Net deferred income tax assets (liabilities)		185
Net deferred income tax assets (liabilities)	(27)
U.S.
Deferred income tax assets:
Allowance for doubtful accounts	2,813	189
Inventories	7,809	7,652
Loss and tax credit carry-forwards	17,431	18,156
Stock-based compensation	506	691
Accrued product warranty	52	43
Accrued compensated absences	328	313
Other reserves	1,009	13
Deferred Tax Assets, Gross, Total	29,948	27,057
Deferred income tax liabilities:
Intangible assets	(960)	(1,386)
Property, plant and equipment and other	(3,271)	(4,919)
Subtotal deferred income tax assets	25,717	20,752
Valuation allowance	(25,717)	(20,752)
Non U.S.
Deferred income tax assets:
Allowance for doubtful accounts	3	3
Inventories	33	79
Loss and tax credit carry-forwards	4,596	4,221
Accrued product warranty	2	4
Property and equipment	501	462
Prepaid income taxes	517	753
Other reserves	9	8
Deferred Tax Assets, Gross, Total	5,661	5,530
Deferred income tax liabilities:
Allowance for doubtful accounts	(11)
Intangible assets		(5)
Property, plant and equipment and other	(31)	(59)
Subtotal deferred income tax assets	5,619	5,466
Valuation allowance	(5,646)	(5,281)
Net deferred income tax assets (liabilities)		$ 185
Net deferred income tax assets (liabilities)	$ (27)