INTANGIBLE ASSETS AND GOODWILL - Summary of Gross Carrying Amounts and Net Book Values of Intangible Assets and Goodwill (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Intangible assets
Gross Carrying Amount	$ 272,010	$ 1,098,588
Accumulated Amortization	(65,382)	(508,263)
Impairment		(189,790)
Total	206,628	400,535
Gross Carrying Amount, Goodwill	9,008	0
Goodwill	$ 9,008	0
INDOCIN | Product Rights
Intangible assets
Remaining useful life	11 years 7 months 6 days
Gross Carrying Amount	$ 154,100	0
Accumulated Amortization	(4,602)	0
Impairment		0
Total	$ 149,498	0
SPRIX | Product Rights
Intangible assets
Remaining useful life	6 years 7 months 6 days
Gross Carrying Amount	$ 39,000	0
Accumulated Amortization	(1,996)	0
Impairment		0
Total	$ 37,004	0
CAMBIA | Product Rights
Intangible assets
Remaining useful life	3 years 2 months 12 days
Gross Carrying Amount	$ 51,360	51,360
Accumulated Amortization	(34,879)	(31,027)
Impairment		0
Total	$ 16,481	20,333
Zipsor | Product Rights
Intangible assets
Remaining useful life	1 year 6 months
Gross Carrying Amount	$ 27,250	27,250
Accumulated Amortization	(23,797)	(22,044)
Impairment		0
Total	$ 3,453	5,206
OXAYDO | Product Rights
Intangible assets
Remaining useful life	1 year
Gross Carrying Amount	$ 300	0
Accumulated Amortization	(108)	0
Impairment		0
Total	192	0
NUCYNTA | Product Rights
Intangible assets
Gross Carrying Amount	0	1,019,978
Accumulated Amortization	0	(455,192)
Impairment		(189,790)
Total	$ 0	$ 374,996