Income Taxes - Schedule of Components of Deferred Tax Assets and Deferred Tax Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Sep. 30, 2018
Deferred tax assets (liabilities):
Capitalized inventory costs	$ 168	$ 193
Inventory write-downs	2,856	1,333
Accrued warranty	161	204
Deferred profits	346	1,006
Accruals and reserves not currently deductible	3,531	5,017
Stock option expense	849	738
Federal net operating loss carryforwards	6,979	2,922
Foreign and state net operating losses	10,481	13,860
Book vs. tax depreciation and amortization	(1,546)	(1,667)
Other deferred tax assets	75	163
Total deferred tax assets	23,900	23,769
Valuation allowance	(23,900)	(23,769)
Deferred tax assets, net of valuation allowance	$ 0	$ 0