SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details 5) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of year:	$ 33,407	$ 0
Fair value upon reclassification of balance as of January 1, 2013		16,194
Change in fair value of warrant liability included in net loss	4,517	19,799	0
Fair value of warrants exercised	(993)	(2,586)
Balance at end of year:	0	33,407	0
Common stock warrants
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability, Reclassification to Equity	$ (36,931)