STOCK-BASED COMPENSATION - Restricted Stock (Details) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Number of Units
Granted (in units)	2,471,500
Forfeited (in units)	(755,400)
Non-vested at the end (in units)	1,716,100
Weighted Average Grant Date Fair Value (Per Unit)
Granted (per unit)	$ 1.14
Forfeited (per unit)	0.59
Outstanding at the end (per unit)	$ 1.38
2017 Omnibus Incentive Plan | Restricted Stock Units (RSUs)
Number of Units
Non-vested at the beginning (in units)	1,180,882	841,361
Granted (in units)	108,498	753,986
Vested (in units)	(600,900)	(187,956)
Forfeited (in units)	(93,679)	(226,509)
Non-vested at the end (in units)	594,801	1,180,882
Weighted Average Grant Date Fair Value (Per Unit)
Outstanding at the beginning (per unit)	$ 5.44	$ 10.44
Granted (per unit)	2.77	2.45
Vested (per unit)	4.05	10.35
Forfeited (per unit)	9.42	10.16
Outstanding at the end (per unit)	$ 5.72	$ 5.44
Director Group | 2017 Omnibus Incentive Plan | Restricted Stock Units (RSUs)
Number of Units
Granted (in units)	893,996
Non-vested at the end (in units)	340,415
Employee Group | 2017 Omnibus Incentive Plan | Restricted Stock Units (RSUs)
Number of Units
Granted (in units)	1,568,655
Non-vested at the end (in units)	254,386