Income Taxes - Deferred tax assets (liabilities) (Details 2) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Deferred tax assets:
Inventories	$ 604	$ 665
Accrued employees compensation and benefits costs	696	612
Accrued arbitration award and related liability	160	160
Net operating loss and credit carryforwards	244	388
Other	49	52
Minimum pension liability	10	2
Total deferred tax assets	1,763	1,879
Valuation allowance	(253)	(397)
Net deferred tax asset	1,510	1,482
Deferred tax liabilities:
Property, plant and equipment	(1,019)	(972)
Total deferred tax liabilities	(1,019)	(972)
Net deferred tax asset	$ 491	$ 510