5.	Other intangible assets:

Other intangible assets, net, consisting of product rights and licenses are summarized as follows:


December 31, 2017	Gross Carrying Value		Accumulated Amortization			Intangible Assets, net		Weighted average Useful Life
Product rights	$	6,050	$	(4,881	)	$	1,169		1.21
BELBUCA^® license and distribution rights		45,000		(4,500	)		40,500		8.50
Licenses		1,900		(1,709	)		191		0.54

Total intangible assets	$	52,950	$	(11,090	)	$	41,860		10.25


December 31, 2016	Gross Carrying Value		Accumulated Amortization			Intangible Assets, net		Weighted average Useful Life
Product rights	$	9,050	$	(7,052	)	$	1,998		9.11
Licenses		1,900		(1,613	)		287		1.84

Total intangible assets	$	10,950	$	(8,665	)	$	2,285		10.95

The Company incurred amortization expense on other intangible assets of approximately $5.4 million, $1.0 million and $1.0 million for the years ended December 31, 2017, 2016 and 2015, respectively. Estimated aggregate future amortization expenses for other intangible assets for each of the next five years and thereafter are as follows:


Years ending December 31,
2018	$	5,157
2019		5,157
2020		4,547
2021		4,500
2022		4,500
Thereafter		17,999

	$	41,860