STOCK-BASED COMPENSATION (Tables)

12 Months Ended

Dec. 31, 2019

Share-based Payment Arrangement [Abstract]

Key assumptions used in valuing market-based awards

The key assumptions used in valuing these market-based awards were as follows:

	2019		2018
Risk-free interest rate	2.57	%	2.10	%
Dividend yield	—	%	—	%
Expected volatility	85.00	%	100.00	%

Stock-based compensation expense activity

The following table reflects the outstanding RSAs and activity related thereto for the year ended December 31, 2019:

	Service-based Awards			Service and Performance-based Awards			Service and Market-based Awards			Service, Performance, and Market-based Awards
	Number of Shares	Weighted-average Grant Date Fair Value		Number of Shares	Weighted-average Grant Date Fair Value		Number of Shares	Weighted-average Grant Date Fair Value		Number of Shares	Weighted-average Grant Date Fair Value
Outstanding at December 31, 2018	632,759	$	2.72	1,018,500	$	2.70	1,176,600	$	1.67	—	$	—
Shares granted	1,747,200	2.14		—	—		1,254,000	1.82		1,068,000	0.98
Shares forfeited	(32,402)	2.76		(4,000)	2.70		(976,733)	1.70		—	—
Shares vested	(1,933,553)	2.27		(639,500)	2.70		(264,206)	1.67		(360,000)	0.98
Outstanding at December 31, 2019	414,004	$	2.41	375,000	$	2.70	1,189,661	$	1.80	708,000	$	0.98

Performance award assumptions

The assumptions used to estimate the fair value of the 2019 Performance Award II granted as of the date presented are as follows:

			Pre-Modification		At Modification
	January 4, 2019		December 13, 2019		December 13, 2019
Risk-free interest rate	2.57	%	1.53	%	1.53	%
Dividend yield	—	%	—	%	—	%
Expected volatility	85.00	%	65.00	%	65.00	%

The assumptions used to estimate the fair value of the 2018 Performance Award II granted as of the date presented are as follows:

			Pre-Modification		At Modification
	June 1, 2018		December 19, 2018		December 19, 2018
Risk-free interest rate	2.10	%	2.35	%	2.62	%
Dividend yield	—	%	—	%	—	%
Expected volatility	100.00	%	80.00	%	85.00	%