ACCRUED LIABILITIES (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015	Dec. 31, 2014
ACCRUED LIABILITIES
Compensation and fringe benefits	$ 6,827	$ 7,791
Warranty reserve	1,042	780	$ 786
Other accrued expenses	4,584	2,550
Accrued liabilities	$ 12,453	$ 11,121