NET (LOSS) INCOME PER SHARE - Schedule of Anti-Dilutive Shares (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total potentially dilutive common shares (in shares)	35,276	21,632	23,549
Employee Stock Option
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total potentially dilutive common shares (in shares)	6,486	3,701	5,618
Convertible Senior Notes, 2.5% | Convertible debt
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total potentially dilutive common shares (in shares)	13,895	17,931	17,931
Convertible Senior Notes, 5.0% | Convertible debt
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Total potentially dilutive common shares (in shares)	14,895	0	0