Components of Net Deferred Income Tax Asset (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Sep. 30, 2018
Deferred income tax assets:
Allowance for doubtful accounts	$ 192	$ 553
Inventories	7,731	6,938
Loss and tax credit carry-forwards	22,377	21,207
Stock-based compensation	691	614
Accrued product warranty	47	144
Accrued compensated absences	313	259
Property and equipment	462	457
Prepaid income taxes	753	714
Other reserves	21	62
Deferred Tax Assets, Gross, Total	32,587	30,948
Deferred income tax liabilities:
Allowance for doubtful accounts		(6)
Intangible assets	(1,391)	(1,681)
Property, plant and equipment and other	(4,978)	(3,681)
Subtotal deferred income tax assets	26,218	25,580
Valuation allowance	(26,033)	(25,379)
Net deferred income tax assets	185	201
U.S.
Deferred income tax assets:
Allowance for doubtful accounts	189	545
Inventories	7,652	6,870
Loss and tax credit carry-forwards	18,156	17,056
Stock-based compensation	691	614
Accrued product warranty	43	136
Accrued compensated absences	313	259
Prepaid income taxes	753	714
Other reserves	13	56
Deferred Tax Assets, Gross, Total	27,810	26,250
Deferred income tax liabilities:
Intangible assets	(1,386)	(1,681)
Property, plant and equipment and other	(4,919)	(3,622)
Subtotal deferred income tax assets	21,505	20,947
Valuation allowance	(21,502)	(20,931)
Net deferred income tax assets	3	16
Non U.S.
Deferred income tax assets:
Allowance for doubtful accounts	3	8
Inventories	79	68
Loss and tax credit carry-forwards	4,221	4,151
Accrued product warranty	4	8
Property and equipment	462	457
Other reserves	8	6
Deferred Tax Assets, Gross, Total	4,777	4,698
Deferred income tax liabilities:
Allowance for doubtful accounts		(6)
Intangible assets	(5)
Property, plant and equipment and other	(59)	(59)
Subtotal deferred income tax assets	4,713	4,633
Valuation allowance	(4,531)	(4,448)
Net deferred income tax assets	$ 182	$ 185