STOCKHOLDERS' EQUITY (Details 2) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended		12 Months Ended
	Sep. 30, 2015	Feb. 28, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Warrants - issued and outstanding
Issuance of common stock, net of costs (in shares)	2,250,000	2,587,500
Common stock issued, price per share (usd per share)	$ 45.00	$ 20.00
Proceeds from issuance of common stock, net of issuance costs	$ 94,900	$ 48,400	$ 143,293	$ 0	$ 54,196
Number of warrants (in shares)			1,428,383
Number of warrants exercised (in shares)			1,037,330	73,964
Net exercise of warrants (in shares)			809,498	43,526
Common Stock
Warrants - issued and outstanding
Issuance of common stock, net of costs (in shares)			4,837,500		3,337,500
Net exercise of warrants (in shares)			809,498	43,526	108,321
Private Placement April 2011 | April 4, 2011 Warrants
Warrants - issued and outstanding
Exercise price (in dollars per share)			$ 6.74
Number of warrants (in shares)			733,000
Private Placement November 2012 | November 21, 2012 Warrants
Warrants - issued and outstanding
Exercise price (in dollars per share)			$ 7.86
Number of warrants (in shares)			695,383