DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2022 USD ($) segment	Dec. 31, 2021 USD ($)	Mar. 31, 2021 USD ($)	Jan. 01, 2021 USD ($)	Dec. 31, 2020 USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of operating segments | segment	2
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders' equity	$ 184,842	$ 210,296	$ 65,620		$ 107,674
Convertible senior notes, net	$ 223,781	223,403
3.25% Convertible Senior Notes due 2022 | Senior Notes
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Effective interest rate	3.76%
Additional Paid-In Capital
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders' equity	$ 2,300,558	2,294,215	2,263,790		2,348,114
Accumulated Deficit
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders' equity	$ (1,191,720)	(1,156,868)	$ (1,260,978)		(1,320,886)
Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders' equity					(18,969)
Cumulative Effect, Period of Adoption, Adjustment | Accounting Standards Update 2020-06
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Convertible senior notes, net				$ 19,000
Cumulative Effect, Period of Adoption, Adjustment | Additional Paid-In Capital
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders' equity					(64,319)
Cumulative Effect, Period of Adoption, Adjustment | Additional Paid-In Capital | Accounting Standards Update 2020-06
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders' equity		2,700		(67,000)
Cumulative Effect, Period of Adoption, Adjustment | Accumulated Deficit
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders' equity					$ 45,350
Cumulative Effect, Period of Adoption, Adjustment | Accumulated Deficit | Accounting Standards Update 2020-06
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders' equity		$ 2,700		$ 48,000