NET INCOME (LOSS) PER COMMON SHARE - Schedule of Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Numerator:
Net Income (Loss), basic and diluted	$ (29,183)	$ (37,435)	$ 52,198	$ (93,908)
Denominator:
Weighted average number of shares outstanding, basic	180,729	179,048	180,314	178,662
Dilutive Securities, Effect on Basic Earnings Per Share [Abstract]
Weighted-average common shares outstanding, diluted	180,729	179,048	184,344	178,662
Net Income (Loss) per common share, basic (in dollars per share)	$ (0.16)	$ (0.21)	$ 0.29	$ (0.53)
Net Income (Loss) per common share, diluted (in dollars per share)	$ (0.16)	$ (0.21)	$ 0.28	$ (0.53)
Options to purchase common stock
Dilutive Securities, Effect on Basic Earnings Per Share [Abstract]
Effect of dilutive securities	0	0	1,770	0
Unvested restricted stock units
Dilutive Securities, Effect on Basic Earnings Per Share [Abstract]
Effect of dilutive securities	0	0	1,733	0
Common stock potentially issuable for ESPP purchases
Dilutive Securities, Effect on Basic Earnings Per Share [Abstract]
Effect of dilutive securities	0	0	317	0
Common stock held by the NQDC
Dilutive Securities, Effect on Basic Earnings Per Share [Abstract]
Effect of dilutive securities	0	0	210	0