Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Sep. 30, 2016
Deferred Tax Assets:
Net operating income/loss	$ 11,823	$ 10,453
Uniform capitalization and inventory	1,432	1,596
Deferred compensation	2,009	1,853
Stock-based compensation	1,094	760
Reserve for accrued employee benefits	1,208	1,679
Warranty accrual	892	1,388
Goodwill	64	345
Postretirement benefits liability	264	503
Allowance for doubtful accounts	14	220
Accrued legal	435	294
Credit carryforwards	3,258	1,292
Other	44	171
Deferred tax assets	22,537	20,554
Deferred Tax Liabilities:
Depreciation and amortization	(10,002)	(8,247)
Deferred tax liabilities	(10,002)	(8,247)
Less: valuation allowance	(8,767)	(8,439)
Net deferred income tax asset	$ 3,768	$ 3,868