Income Taxes - Summary of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Sep. 30, 2017
Deferred tax assets:
Net U.S. operating loss carryforwards	$ 3,200	$ 5,188
Net non-U.S. operating loss carryforwards	592	596
Employee benefits	1,656	2,461
Inventory reserves	1,029	1,240
Allowance for doubtful accounts	126	135
Intangibles	2,826	4,873
Foreign tax credits	1,956	602
Other tax credits	1,164	994
Other	1,015	1,126
Total deferred tax assets	13,564	17,215
Deferred tax liabilities:
Depreciation	(5,449)	(8,854)
Unremitted foreign earnings	0	(65)
Prepaid expenses	(296)	(247)
Other	(1,832)	(1,718)
Total deferred tax liabilities	(7,577)	(10,884)
Net deferred tax assets	5,987	6,331
Valuation allowance	(8,400)	(9,597)
Net deferred tax liabilities	$ (2,413)	$ (3,266)