Intangible Assets

6 Months Ended

Jun. 30, 2015

(5) Intangible Assets

Intangible assets other than goodwill as of June 30, 2015 and December 31, 2014 were as follows:



	2015						2014
(in thousands)	Gross		Accumulated Amortization		Net		Gross		Accumulated Amortization		Net		Useful Life (in years)	Weighted Average Useful Life Remaining (in years)
Intangible assets with finite lives:
Licenses	$	5,875	$	(5,875)	$	—	$	5,875	$	(5,875)	$	—	N/A	N/A
Patent costs		21,304		(7,906)		13,398		20,733		(7,369)		13,364	5-20	3
Acquired technology		74,096		(24,427)		49,669		57,383		(18,241)		39,142	3-10	4
Internally developed software		9,072		(6,238)		2,834		9,073		(5,517)		3,556	1-8	<1
Customer relationships		193,015		(47,426)		145,589		157,139		(36,975)		120,164	3-11	2
Non-compete agreements		35,526		(14,301)		21,225		35,469		(11,784)		23,685	3-11	3
Trade names		29,881		(5,890)		23,991		21,800		(4,455)		17,345	2-10	5
Other		41,690		(10,910)		30,780		39,100		(6,905)		32,195	4-10	1
Intangible assets with indefinite lives:
Trademarks		—		—		—		2,110		—		2,110	N/A	N/A
Total intangible assets	$	410,459	$	(122,973)	$	287,486	$	348,682	$	(97,121)	$	251,561	1-20	4

For the quarter and six months ended June 30, 2015, the Company capitalized $357 and $560, respectively, of costs incurred to internally develop and extend patents in the United States and various other countries, compared to $172 and $382, respectively, for the quarter and six months ended June 30, 2014.

For the quarter and six months ended June 30, 2015, amortization expense on intangible assets was $17,481 and $31,997, respectively, compared to $8,211 and 17,414, respectively, for the quarter and six months ended June 30, 2014.

For the years ended 2015, 2016, 2017, 2018, and 2019, annual amortization expense on intangible assets is expected to be $61,040, $54,704, $47,189, $39,046 and $28,471, respectively.