NET INCOME (LOSS) PER SHARE - Antidilutive Shares (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares	11,600	43,923
Stock options and RSU's
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares	850	23,073
Performance stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares	10,750	18,000
Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares	0	2,850