INCOME TAXES - Deferred income tax assets and liabilities (Details 2) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Deferred tax assets:
Allowance for doubtful accounts	$ 78	$ 94
Accruals and reserves	3,468	3,767
Other	179	222
Total deferred tax assets	3,725	4,083
Deferred tax liabilities:
Property, plant, and equipment	2,499	2,184
Total deferred tax liabilities	2,499	2,184
Net deferred tax asset	$ 1,226	$ 1,899