Goodwill and Intangible Assets, Net

Goodwill

Changes in the carrying amount of goodwill were as follows:



(In thousands)
Balance at December 31, 2017	$	48,651
Foreign exchange effects	(129		)
Balance at June 30, 2018	$	48,522

Intangible Assets, Net

The components of intangible assets, net were as follows:



	June 30, 2018							December 31, 2017
(In thousands)	Gross ⁽¹⁾		Accumulated Amortization ⁽¹⁾			Net		Gross ⁽¹⁾		Accumulated Amortization ⁽¹⁾			Net
Distribution rights	$	335	$	(176	)	$	159	$	344	$	(165	)	$	179
Patents	13,662		(5,218		)	8,444		13,250		(5,310		)	7,940
Trademarks and trade names	2,786		(1,746		)	1,040		2,786		(1,594		)	1,192
Developed and core technology	12,560		(7,079		)	5,481		12,560		(6,071		)	6,489
Capitalized software development costs	198		(113		)	85		142		(77		)	65
Customer relationships	32,534		(21,035		)	11,499		32,534		(19,395		)	13,139
Order backlog	—		—			—		150		(113		)	37
Total intangible assets, net	$	62,075	$	(35,367	)	$	26,708	$	61,766	$	(32,725	)	$	29,041


⁽¹⁾	This table excludes the gross value of fully amortized intangible assets totaling $6.8 million and $6.0 million at June 30, 2018 and December 31, 2017, respectively.

Amortization expense is recorded in selling, general and administrative expenses, except amortization expense related to capitalized software development costs and order backlog, which are recorded in cost of sales. Amortization expense by income statement caption was as follows:



	Three Months Ended June 30,				Six Months Ended June 30,
(In thousands)	2018		2017		2018		2017
Cost of sales	$	18	$	55	$	73	$	74
Selling, general and administrative expenses	1,758		1,736		3,505		3,317
Total amortization expense	$	1,776	$	1,791	$	3,578	$	3,391

Estimated future annual amortization expense related to our intangible assets at June 30, 2018, was as follows:



(In thousands)
2018 (remaining 6 months)	$	3,506
2019	6,922
2020	5,791
2021	2,253
2022	2,143
Thereafter	6,093
Total	$	26,708