NOTE 6. INTANGIBLE ASSETS

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


	December 31, 2017							December 31, 2016
	Remaining	Gross						Gross
	Useful Life	Carrying		Accumulated		Net Book		Carrying		Accumulated		Net Book
Product rights	(In years)	Amount		Amortization		Value		Amount		Amortization		Value
NUCYNTA	8.0	$	1,019,978	$	(266,590)	$	753,388	$	1,019,978	$	(172,288)	$	847,690
CAMBIA	6.0		51,360		(20,755)		30,605		51,360		(15,619)		35,741
Lazanda	—		—		—		—		10,480		(3,979)		6,501
Zipsor	4.3		27,250		(17,370)		9,880		27,250		(15,033)		12,217
		$	1,098,588	$	(304,715)	$	793,873	$	1,109,068	$	(206,919)	$	902,149

In November 2017, the Company entered into definitive agreements with Slán Medicinal Holdings Limited (Slán) pursuant to which the Company acquired Slán’s rights to market the specialty drug cosyntropin (Synthetic ACTH Depot) in the U.S., and Slán acquired the Company’s rights to Lazanda (fentanyl) nasal spray. Consequently, the due to the divestiture of Lazanda the Company derecognized the Lazanda product rights in November 2017. See note 14 for additional information related to these audited consolidated financial statements for further information on the divestiture.

In September 2016, the United States District Court for the District of New Jersey ruled in favor of the Company in the Company's patent litigation against all three filers of Abbreviated New Drug Applications (ANDAs) for the Company’s NUCYNTA franchise. With the court’s ruling, the Company expects market exclusivity until December 2025 for NUCYNTA ER, NUCYNTA and NUCYNTA oral solution (an unmarketed form of NUCYNTA). In light of this court ruling, the Company reviewed the useful life of the NUCYNTA product rights and extended that from the previous estimate of June 2025 to December 2025. The change in the useful life reduced the amortization charge for 2016 by $1.3 million.

In June 2015, the Company entered into a settlement agreement in its ongoing patent litigation related to an Abbreviated New Drug Application (ANDA) seeking approval to market a generic version of Zipsor (diclofenac liquid filled capsules) 25mg tablets. The settlement permits defendant Watson Laboratories Inc. to begin selling generic Zipsor on March 24, 2022, or earlier under certain circumstances. The settlement concluded all ongoing ANDA litigation related to Zipsor. In light of this settlement agreement, the Company reviewed the useful life of the Zipsor product rights and, as of June 2015, extended that from the previous estimate of July 2019 to March 2022. The change in the useful life reduced the amortization charge for 2015 by $0.9 million.

Based on finite-lived intangible assets recorded as of December 31, 2017, 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):


	Estimated
	Amortization
Year Ending December 31,	Expense
2018	$	101,774
2019		101,774
2020		101,774
2021		101,774
2022		99,969
Thereafter		286,808
Total	$	793,873