STOCKHOLDERS' DEFICIT - Carrying Value of Series A and C Preferred Stock (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Convertible Preferred Stock
Class of Stock [Line Items]
Fair value assumptions, dividend yield (as a percent)	11.50%
Series A Preferred Stock
Increase (Decrease) in Temporary Equity [Roll Forward]
Preferred stock carrying value, beginning of period	$ 2,462	$ 62,918
Exchange of Series A for Series C		(60,776)
Accretion of discount related to beneficial conversion feature	53	40
Dividends Recorded	312	280
Preferred stock carrying value, at end of period	2,827	2,462
Series C Preferred Stock
Increase (Decrease) in Temporary Equity [Roll Forward]
Preferred stock carrying value, beginning of period	69,540	0
Exchange of Series A for Series C		60,776
Accretion of discount related to beneficial conversion feature	648	652
Dividends Recorded	9,064	8,112
Preferred stock carrying value, at end of period	$ 79,252	$ 69,540