INTANGIBLE ASSETS (Tables)

12 Months Ended

Dec. 31, 2015

INTANGIBLE ASSETS.

Summary of the gross carrying amounts and net book values of our intangible assets

        The gross carrying amounts and net book values of our intangible assets were as follows (in thousands):

	December 31, 2015									December 31, 2014
Amounts in thousands	Remaining Useful Life (In years)		Gross Carrying Amount		Accumulated Amortization			Net Book Value		Gross Carrying Amount		Accumulated Amortization			Net Book Value
NUCYNTA product rights		9.5	$	1,019,977	$	(74,080	)	$	945,897	$	—	$	—		$	—
CAMBIA product rights		8.0		51,360		(10,483	)		40,877		51,360		(5,347	)		46,013
Lazanda product rights		6.6		10,480		(2,814	)		7,666		10,480		(1,650	)		8,830
Zipsor product rights		6.3		27,250		(12,696	)		14,554		27,250		(9,732	)		17,518
			$	1,109,067	$	(100,073	)	$	1,008,994	$	89,090	$	(16,729	)	$	72,361

Summary of the future amortization expenses of intangible assets

        Based on finite-lived intangible assets recorded as of December 31, 2015, and assuming the underlying assets will not be impaired and that we will not change the expected lives of the assets, future amortization expenses were estimated as follows (in thousands):

Year Ending December 31,	Estimated Amortization Expense
2016	$	108,147
2017		108,147
2018		108,147
2019		108,147
2020		108,147
Thereafter		468,259
Total	$	1,008,994