Income Taxes - Summary of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Sep. 30, 2018
Deferred tax assets:
Net U.S. operating loss carryforwards	$ 5,002	$ 3,200
Net non-U.S. operating loss carryforwards	866	592
Employee benefits	2,456	1,656
Inventory reserves	970	1,029
Allowance for doubtful accounts	144	126
Intangibles	2,535	2,826
Foreign tax credits	1,724	1,956
Other tax credits	1,232	1,164
Other	918	1,015
Total deferred tax assets	15,847	13,564
Deferred tax liabilities:
Depreciation	(8,135)	(5,449)
Prepaid expenses	(192)	(296)
Other	(1,681)	(1,832)
Total deferred tax liabilities	(10,008)	(7,577)
Net deferred tax assets	5,839	5,987
Valuation allowance	(7,557)	(8,400)
Net deferred tax liabilities	$ (1,718)	$ (2,413)