DISPOSITIONS - Sale of NUCYNTA (Details) $ in Millions		1 Months Ended	12 Months Ended
	Feb. 13, 2020 USD ($) payment	Feb. 11, 2020 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Inventory transfer				$ 9.0
NUCYNTA | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration received	$ 367.9
Proceeds from divestiture of businesses, base purchase price	375.0
Consideration received, inventory adjustment upon disposal	$ 6.0
Royalties received		$ 13.1
Number of lump sum payments | payment	2
Gain (loss) on disposal			$ (15.8)
Carrying value of intangible derecognized				369.1
Accrued third-party consent fees				$ 9.0
Net proceeds received			$ 1.0
NUCYNTA | Disposal Group, Disposed of by Sale, Not Discontinued Operations | Third-Party Consent Agreement
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Lump sum payments obligation	$ 4.5