DEBT - Summary of debt (Details) - USD ($)
$ in Thousands
Jun. 30, 2015
Dec. 31, 2014
Debt Instrument [Line Items]    
Long-term debt, total $ 21,382 $ 23,601
Less current portion of long-term debt 3,908 4,251
Noncurrent portion of long-term debt 17,474 19,350
Note payable to Silicon Valley Bank, with interest at our option of prime rate or LIBOR rate plus margin    
Debt Instrument [Line Items]    
Long-term debt, total 21,224 23,125
Seller financed note payable, with interest at 4.25%, monthly payments of principal and interest, secured by equipment, due September 2015    
Debt Instrument [Line Items]    
Long-term debt, total $ 158 $ 476