Income Taxes (Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Sep. 30, 2017
Deferred tax assets - current:
Capitalized inventory costs	$ 193	$ 210
Inventory write-downs	1,333	1,945
Accrued warranty	204	260
Deferred profits	1,006	1,190
Accruals and reserves not currently deductible	5,017	1,945
Deferred tax assets (liabilities)- non-current:
Stock option expense	738	1,080
Book vs. tax basis of acquired assets	0	(1,290)
Federal net operating loss carryforwards	2,922	4,820
Foreign and state net operating losses	13,860	14,800
Book vs. tax depreciation and amortization	(1,667)	(2,250)
Foreign tax credits	0	420
Other deferred tax assets	163	0
Total deferred tax assets	23,769	23,130
Valuation allowance	(23,769)	(22,930)
Deferred tax assets, net of valuation allowance	$ 0	$ 200