FAIR VALUE MEASUREMENTS - RECURRING BASIS (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Liabilities that are measured at fair value on a recurring basis
Warrant liabilities	$ 757
Change in the estimated fair value of warrant liabilities
Balance at December 31, 2015	757
Increase in fair value	1,640	$ 317
Balance at March 31, 2016	2,397
Recurring
Liabilities that are measured at fair value on a recurring basis
Warrant liabilities	757
Change in the estimated fair value of warrant liabilities
Balance at December 31, 2015	757
Balance at March 31, 2016	2,397
Recurring | Level 2
Liabilities that are measured at fair value on a recurring basis
Warrant liabilities	757
Change in the estimated fair value of warrant liabilities
Balance at December 31, 2015	757
Balance at March 31, 2016	2,397
Recurring | Level 3
Liabilities that are measured at fair value on a recurring basis
Warrant liabilities	0
Change in the estimated fair value of warrant liabilities
Balance at December 31, 2015	0
Balance at March 31, 2016	$ 0