STOCKHOLDERS' DEFICIT - Carrying Value of Preferred Stock Narrative (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Series A Preferred Stock
Class of Warrant or Right [Line Items]
Dividend accrual rate	11.50%
Convertible preferred stock series, liquidation preference	$ 2,833	$ 2,603
Series C Preferred Stock
Class of Warrant or Right [Line Items]
Dividend accrual rate	11.50%
Convertible preferred stock series, liquidation preference	$ 82,173	$ 75,491