FAIR VALUES OF ASSETS AND LIABILITIES (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2012
Assets and liabilities measured at fair value on a recurring basis
Derivative warrant liability	$ 1,907	$ 7,224	$ 14,585
Recurring basis
Assets and liabilities measured at fair value on a recurring basis
Cash equivalents	20,078	13,190
Derivative warrant liability	1,907	7,224
Recurring basis | Level 1
Assets and liabilities measured at fair value on a recurring basis
Cash equivalents	20,078	13,190
Recurring basis | Level 2
Assets and liabilities measured at fair value on a recurring basis
Derivative warrant liability	$ 1,907	$ 7,224