STOCK-BASED COMPENSATION (Tables)

12 Months Ended

Dec. 31, 2018

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Schedule of Changes in Outstanding Stock Options

Stock options and stock appreciation rights outstanding at December 31, 2018 and changes during the year ended December 31, 2018 is as follows:



	December 31, 2018
	Shares		Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (In Years)	Aggregate Intrinsic Value
	(Shares and intrinsic value in thousands)
Outstanding at January 1, 2018	47,115		$	3.25
Granted	—		—
Exercised	(11,049	)	2.02
Forfeited	(2,668	)	4.84
Expired	(240	)	17.67
Outstanding at December 31, 2018	33,158		$	3.42	6.9	$	420,201
Exercisable	17,612		$	2.78	6.1	$	234,922

Schedule of Information for Stock Options Outstanding and Exercisable

The following table summarizes the information about stock options and stock appreciation rights outstanding and exercisable at December 31, 2018:



	Awards Outstanding				Awards Exercisable
Range of Exercise Prices	Outstanding at December 31, 2018	Weighted Average Remaining Contractual Life in Years	Weighted Average Exercise Price		Exercisable at December 31, 2018	Weighted Average Remaining Contractual Life in Years	Weighted Average Exercise Price
	(Shares in thousands)
$0.01 to $3.00	16,404	5.7	$	1.55	11,666	5.2	$	1.28
$3.01 to $6.00	15,044	8.1	4.53		5,049	8.1	4.53
$6.01 to $9.00	327	5.7	7.73		217	5.2	7.93
$9.01 to $12.00	826	8.4	10.65		311	7.4	10.40
$12.01 to $15.00	390	7.3	13.01		202	5.9	13.25
$15.01 to $18.00	1	3.2	15.47		1	3.2	15.47
$18.01 to $21.00	115	4.2	19.88		115	4.2	19.88
$21.01 to $24.00	51	3.9	22.66		51	3.9	22.66
	33,158	6.9	3.42		17,612	6.1	2.78

Schedule of Weighted Average Assumptions

The following are the weighted average assumptions used in the Black-Scholes option pricing model:



	Years Ended December 31,
	2017		2016
Expected volatility	50	%	44	%
Risk-free interest rate	2.0	%	0.8	%
Expected term	5.5 years		3.2 years
Dividend yield	—	%	—	%

Schedule of Outstanding Unvested RSUs

Prior to the Combination, there were no RSUs outstanding. Unvested RSUs outstanding at December 31, 2018 and changes during the year ended December 31, 2018 are as follows:



	RSUs
	Number of Shares		Weighted Average Grant Date Fair Value
	(Shares in thousands)
Unvested at January 1, 2018	2,895		$	12.48
Granted	3,537		18.08
Vested	(1,221	)	12.23
Forfeited	(600	)	12.55
Unvested at December 31, 2018	4,611		$	16.77