ACCRUED LIABILITIES (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
ACCRUED LIABILITIES
Compensation and fringe benefits	$ 6,178	$ 7,791
Warranty reserve	1,073	780	$ 786
Other accrued expenses	5,762	2,550
Accrued liabilities	$ 13,013	$ 11,121