Income Taxes (Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Sep. 30, 2016
Deferred tax assets - current:
Capitalized inventory costs	$ 210	$ 270
Inventory write-downs	1,945	2,460
Accrued warranty	260	160
Deferred profits	1,190	1,180
Accruals and reserves not currently deductible	1,945	1,720
Deferred tax assets - current	5,550	5,790
Valuation allowance	(5,550)	(5,790)
Deferred tax assets - current	0	0
Deferred tax assets (liabilities)- non-current:
Stock option expense	1,080	890
Book vs. tax basis of acquired assets	(1,290)	(1,340)
Federal net operating loss carryforwards	4,820	3,370
Foreign and state net operating losses	14,800	13,200
Book vs. tax depreciation and amortization	(2,250)	(2,200)
Foreign tax credits	420	4,230
Other deferred tax assets	0	570
Total deferred tax assets - non-current	17,580	18,720
Valuation allowance	(17,380)	(18,520)
Deferred tax assets (liabilities) - non-current, net of valuation allowance	$ 200	$ 200