LONG-TERM DEBT AND COMMITMENTS (Narrative) (Details) - USD ($)			3 Months Ended		9 Months Ended
	May 29, 2013	Apr. 09, 2013	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	May 21, 2013
FDA Approval Qsymia (PMR and CVOT) Member
Long-term debt
Contractual Obligation Term					5 years
Minimum | FDA Approval Qsymia (PMR and CVOT) Member
Long-term debt
Contractual Obligation			$ 180,000,000		$ 180,000,000
Maximum | FDA Approval Qsymia (PMR and CVOT) Member
Long-term debt
Contractual Obligation			220,000,000		220,000,000
Convertible Senior Notes Due 2020
Long-term debt
Offering amount							$ 220,000,000
Interest rate (as a percent)							4.50%
Increase in debt instrument face amount	$ 30,000,000
Conversion price per share (in dollars per share)	$ 14.86
Net proceeds from offering	$ 241,800,000
Total interest expense recognized			8,300,000	$ 7,500,000	24,300,000	$ 22,100,000
Amortization of debt discount			4,900,000	4,400,000	14,300,000	13,000,000
Amortization of deferred financing costs			259,000	235,000	758,000	689,000
Senior Secured Notes Due 2018
Long-term debt
Total interest expense recognized			700,000	1,300,000	2,700,000	3,600,000
Amortization of deferred financing costs			$ 46,000	$ 46,000	$ 126,000	$ 189,000
Amount received		$ 50,000,000
Amount received in funding and facility payments		$ 500,000
Amount due as a percentage of net sales, if scheduled quarterly payments are less than 25% of the net sales			25.00%		25.00%
Make-whole premium ratio			1.03		1.03