NET (LOSS) INCOME PER SHARE (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Antidilutive Securities Excluded from Computation of Earnings Per Share
Net (loss) income	$ (20,989)	$ (13,290)	$ (5,380)	$ (5,211)	$ 2,169	$ (8,072)	$ (1,712)	$ (3,018)	$ (4,491)	$ 4,208	$ 8,353	$ 12,985	$ (44,870)	$ (10,634)	$ 21,055
Weighted average number of common shares									299,518	298,510	298,237	298,242	337,297	313,887	298,772
Effect of employee stock-based awards															1,702
Diluted shares outstanding									301,102	301,045	299,791	298,554	337,297	313,887	300,474
Net (loss) income per share:
Basic and Diluted (in dollars per share)	$ (0.06)	$ (0.04)	$ (0.02)	$ (0.02)	$ 0.01	$ (0.03)	$ (0.01)	$ (0.01)	$ (0.01)	$ 0.01	$ 0.03	$ 0.04	$ (0.13)	$ (0.03)	$ 0.07
Options
Antidilutive Securities Excluded from Computation of Earnings Per Share
Options outstanding not included in the computation of diluted weighted average shares because their effect would have been anti-dilutive (in shares)													2,000
Average exercise price of options outstanding (in dollars per share)													$ 3.91
Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share
Options outstanding not included in the computation of diluted weighted average shares because their effect would have been anti-dilutive (in shares)														10,350
Price per common share for each warrant					$ 2.70									$ 2.70