(5) Intangible Assets

Intangible assets other than goodwill at June 30, 2013 and December 31, 2012 were as follows:



	2013						2012
(in thousands)	Gross		Accumulated Amortization		Net		Gross		Accumulated Amortization		Net		Useful Life (in years)
Intangible assets with finite lives:
Licenses	$	5,875	$	(5,875)	$	—	$	5,875	$	(5,875)	$	—
Patent costs		30,335		(14,306)		16,029		27,635		(14,047)		13,588	6 - 7
Acquired technology		26,201		(12,599)		13,602		26,262		(11,852)		14,410	5 - 10
Internally developed software		17,847		(12,143)		5,704		17,847		(11,424)		6,423	5
Customer relationships		89,587		(12,011)		77,576		60,329		(7,754)		52,575	5 - 13
Non-compete agreements		15,087		(5,203)		9,884		14,051		(3,836)		10,215	3 - 11
Trade names		8,529		(1,375)		7,154		5,814		(723)		5,091	2 - 10
Other		11,206		(3,636)		7,570		6,356		(3,051)		3,305	<1 - 7
Intangibles with indefinite lives:
Trademarks		2,110		—		2,110		2,770		—		2,770	N/A
Total intangible assets	$	206,777	$	(67,148)	$	139,629	$	166,939	$	(58,562)	$	108,377	<1 - 13

For the six months ended June 30, 2013 and 2012, the Company capitalized $1,313 and $389, respectively, of costs incurred to acquire, develop and extend patents in the United States and various other countries.

Amortization expense for intangible assets for the quarter and six months ended June 30, 2013 was $5,084 and $8,896, respectively, compared to $3,021 and $6,440, respectively, for the quarter and six months ended June 30, 2012.

Annual amortization expense for intangible assets for 2013, 2014, 2015, 2016 and 2017 is expected to be $11,034, $18,613, $16,756, $14,889 and $13,481, respectively.