Income Taxes - Summary of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Sep. 30, 2016
Deferred tax assets:
Net U.S. operating loss carryforwards	$ 5,188	$ 195
Net non-U.S. operating loss carryforwards	596	777
Employee benefits	2,461	3,366
Inventory reserves	1,240	1,032
Allowance for doubtful accounts	135	234
Capitalized research and development expenses	0	870
Intangibles	4,873	4,364
Foreign tax credits	602	575
Other tax credits	994	1,006
Other	1,126	1,106
Total deferred tax assets	17,215	13,525
Deferred tax liabilities:
Depreciation	(8,854)	(10,777)
Unremitted foreign earnings	(65)	(65)
Prepaid expenses	(247)	(566)
Other tax credits	(1,718)	(647)
Total deferred tax liabilities	(10,884)	(12,055)
Net deferred tax assets (liabilities)	6,331	1,470
Valuation allowance	(9,597)	(4,399)
Net deferred tax liabilities	$ (3,266)	$ (2,929)