STOCKHOLDERS' EQUITY (Series C Preferred Stock) (Details) - USD ($) $ / shares in Units, $ in Millions	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Nov. 06, 2017
Class of Stock [Line Items]
Preferred stock, par value (in dollars per share)	$ 0.01		$ 0.01
Preferred stock, shares authorized (in shares)	15,000,000		15,000,000
Preferred stock, shares outstanding (in shares)	47		47
Preferred stock, shares issued (in shares)	47		47
Series C Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, par value (in dollars per share)					$ 0.01
Number of shares converted (in shares)		2,548
Preferred stock, shares authorized (in shares)	2,748		2,748		2,748
Preferred stock, shares outstanding (in shares)	0		0
Preferred stock, shares issued (in shares)	2,748		2,748
Preferred Stock, Liquidation Preference Per Share					$ 1,000
Common stock issued on conversion of preferred shares		223,022
Placement Agreement | Series C Preferred Stock [Member]
Class of Stock [Line Items]
Conversion price (in dollars per share)				$ 21.00
2018 Purchase Agreement | Series C Preferred Stock [Member]
Class of Stock [Line Items]
Conversion price (in dollars per share)	$ 15.60
2018 Purchase Agreement | Series C Preferred Stock [Member] | Deemed Dividend C
Class of Stock [Line Items]
Beneficial conversion feature	$ 0.8