DEBT (Details) $ / shares in Units, $ in Thousands			3 Months Ended	6 Months Ended
	Apr. 02, 2015 USD ($)	Sep. 09, 2014 USD ($) $ / shares	Jun. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Dec. 31, 2014 USD ($)
Carrying amounts of debt
Net carrying amount of the Senior Notes			$ 562,516	$ 562,516
Net carrying amount of the Convertible Notes			236,315	236,315	$ 229,891
Interest expense incurred
Unamortized discount and debt issuance costs			114,900	114,900
Convertible notes due 2021
Interest expense incurred
Unamortized discount and debt issuance costs			108,700	108,700
Other Assets
Interest expense incurred
Unamortized discount and debt issuance costs			6,200	6,200
Senior Secured Notes
Long-term debt
Principal amount	$ 575,000		575,000	575,000
Proceeds from the issuance of debt	$ 562,000
April 2, 2018				57,500
April 2, 2019				115,000
April 2, 2020				115,000
April 2, 2021				143,750
April 2, 2022				143,750
Amount that can be paid after first year but before second anniversary				100,000
Threshold limit to repay principal amount outstanding in full				100,000
Threshold limit of asset dispositions which is required to make mandatory prepayments on senior notes				10,000
Carrying amounts of debt
Principal amount of the Notes			575,000	575,000
Unamortized debt discount balance			(12,484)	(12,484)
Debt issuance costs			0	500
Net carrying amount of the Senior Notes			562,516	562,516
Interest expense incurred
Stated coupon interest			15,281	15,281
Amortization of debt discount and debt issuance costs			471	471
Total interest expense			15,752	15,752
Senior Secured Notes | Three month LIBOR
Long-term 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 Secured Notes | NUCYNTA
Long-term debt
Proceeds from the issuance of debt	$ 550,000
Convertible notes due 2021
Long-term debt
Principal amount		$ 345,000	$ 345,000	$ 345,000	$ 345,000
Interest rate (as a percent)		2.50%	2.50%	2.50%
Net proceeds from debt offering		$ 334,200
Underwriting discount		10,400
Offering expenses		$ 400
Conversion rate of common stock per $1,000 principal amount		51.9852
Conversion price of common stock (in dollars per share) | $ / shares		$ 19.24
Redeemable principal amount of debt (as a percent)		100.00%
Effective interest rate (as a percent)		9.34%
Carrying amounts of debt
Principal amount of the Notes			$ 345,000	$ 345,000
Unamortized debt discount balance		$ (119,000)	(108,685)	(108,685)
Net carrying amount of the Convertible Notes		226,000	236,315	236,315
Interest expense incurred
Stated coupon interest			2,156	4,312
Amortization of debt discount and debt issuance costs			3,513	6,934
Total interest expense			$ 5,669	$ 11,246
Convertible notes due 2021 | Other Assets
Carrying amounts of debt
Debt issuance costs		7,100
Convertible notes due 2021 | Additional Paid-In Capital
Long-term debt
Equity issuance costs		$ 3,700