DEBT (Details)			1 Months Ended	9 Months Ended	12 Months Ended
	Apr. 02, 2015 USD ($)	Sep. 09, 2014 USD ($) $ / shares	Apr. 30, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Oct. 31, 2013
Debt
Effective interest rate (as a percent)								10.00%
Equity component of convertible debt issued, net of tax							$ 73,272,000
Payment of a prepayment fee					$ 5,000,000
Loss on prepayment of debt					(5,777,000)
Carrying amounts of the liability component
Net carrying amount of the liability component				$ 237,313,000	252,725,000	$ 237,313,000
Net carrying amount of the Notes				563,012,000	466,051,000	563,012,000
Interest expense incurred
Contractual/Stated coupon interest							2,683,000
Amortization of debt discount and debt issuance costs							4,200,000
Total interest expense							$ 6,883,000
Deferred Tax Liability Convertible Debt				36,985,000	$ 31,706,000	36,985,000
Convertible Notes
Debt
Equity component of convertible debt issued, net of tax		$ 73,300,000
Senior Notes
Debt
Aggregate principal amount of notes issued	$ 575,000,000		$ 475,000,000
Effective interest rate (as a percent)					10.75%
Proceeds from the issuance of debt	$ 562,000,000
April 2, 2018					$ 57,500,000
April 2, 2019					115,000,000
April 2, 2020					115,000,000
April 2, 2021					143,750,000
April 2, 2022					43,750,000
Threshold limit to repay principal amount outstanding in full					100,000,000
Threshold limit of asset dispositions which is required to make mandatory prepayments on senior notes					10,000,000
Amount of debt prepaid			100,000,000
Payment of a prepayment fee			5,000,000
Loss on prepayment of debt			(5,800,000)
Unamortized balances of debt discount and debt issuance costs			$ 800,000
Principal amount					475,000,000
Carrying amounts of the liability component
Principal amount of the Notes				575,000,000	475,000,000	575,000,000
Unamortized debt discount balance				(11,527,000)	(8,605,000)	(11,527,000)
Unamortized debt issuance costs				(461,000)	(344,000)	(461,000)
Net carrying amount of the Notes				563,012,000	466,051,000	563,012,000
Interest expense incurred
Contractual/Stated coupon interest					54,722,000	46,874,000
Amortization of debt discount and debt issuance costs					2,261,000	1,466,000
Total interest expense					56,983,000	48,340,000
Senior Notes | Prior to Second Anniversary
Debt
Prepayment premium	5.00%
Senior Notes | After Second Anniversary and on or Prior to Third Anniversary
Debt
Prepayment premium	4.00%
Senior Notes | After Third Anniversary and on or Prior to Fourth Anniversary
Debt
Prepayment premium	3.00%
Senior Notes | After Fourth Anniversary and on or Prior to Fifth Anniversary
Debt
Prepayment premium	2.00%
Senior Notes | After Fifth Anniversary and on or Prior to Sixth Anniversary
Debt
Prepayment premium	1.00%
Senior Notes | After Sixth Anniversary
Debt
Prepayment premium	0.00%
Senior Notes | Other Assets
Debt
Debt issuance costs				500,000
Senior Notes | Three month LIBOR
Debt
Basis spread (as a percent)	9.75%
Debt instrument, floor rate (as a percent)	1.00%
Interest rate through third anniversary (as a percent)	11.95%
Interest rate after third anniversary (as a percent)	12.95%
Senior Notes | NUCYNTA
Debt
Proceeds from the issuance of debt	$ 550,000,000
Convertible Notes
Debt
Aggregate principal amount of notes issued		345,000,000			$ 345,000,000
Net proceeds from debt offering		334,200,000
Underwriting discount		10,400,000
Offering expenses		$ 400,000
Interest rate (as a percent)		2.50%			2.50%
Conversion rate of common stock per $1 of principal amount		0.0519852
Conversion price (in dollars per share) | $ / shares		$ 19.24
Effective interest rate (as a percent)		9.34%
Liability component of debt		$ 226,000,000
Equity component of debt		$ 119,000,000
Consecutive trading days, period		30 days
Stock price trigger | $ / shares		$ 25.01
Stock price trigger (as a percent)		130.00%
Business days, period		5 days
Principal amount		$ 1,000
Maximum product of the closing sale price of shares of the Company's common stock and the applicable conversion rate for such trading day (as a percent)		98.00%
Observation period		40 days
Carrying amounts of the liability component
Principal amount of the Notes				345,000,000	$ 345,000,000	345,000,000
Unamortized debt discount balance				(101,965,000)	(87,570,000)	(101,965,000)
Unamortized debt issuance costs				(5,722,000)	(4,705,000)	(5,722,000)
Net carrying amount of the Notes				$ 237,313,000	252,725,000	237,313,000
Interest expense incurred
Contractual/Stated coupon interest					8,625,000	8,625,000
Amortization of debt discount and debt issuance costs					15,412,000	14,163,000
Total interest expense					$ 24,037,000	$ 22,788,000
Convertible Notes | Other Assets
Debt
Debt issuance costs		$ 7,100,000
Convertible Notes | Additional Paid-In Capital
Debt
Equity issuance costs		$ 3,700,000