DERIVATIVE INSTRUMENTS - CHANGES IN DERIVATIVE WARRANT LIABILITY (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Changes in Derivative Warrant Liability
Balance at beginning of year	$ 1,907
Issuance of warrants			$ 6,848
Fair value of derivative warrant liability reclassified to additional paid-in capital		$ (16,121)
Balance at end of period	1,314	1,907
Warrants
Changes in Derivative Warrant Liability
Balance at beginning of year	1,907	7,224
Issuance of warrants			6,848
(Decrease) increase in the fair value of the warrants	(593)	10,804	376
Fair value of derivative warrant liability reclassified to additional paid-in capital		(16,121)
Balance at end of period	$ 1,314	$ 1,907	$ 7,224