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	(142		)
Balance at September 30, 2018	$	48,509

Intangible Assets, Net

The components of intangible assets, net were as follows:



	September 30, 2018							December 31, 2017
(In thousands)	Gross ⁽¹⁾		Accumulated Amortization ⁽¹⁾			Net		Gross ⁽¹⁾		Accumulated Amortization ⁽¹⁾			Net
Distribution rights	$	333	$	(182	)	$	151	$	344	$	(165	)	$	179
Patents	14,194		(5,502		)	8,692		13,250		(5,310		)	7,940
Trademarks and trade names	2,786		(1,823		)	963		2,786		(1,594		)	1,192
Developed and core technology	12,560		(7,583		)	4,977		12,560		(6,071		)	6,489
Capitalized software development costs	249		(131		)	118		142		(77		)	65
Customer relationships	32,534		(21,855		)	10,679		32,534		(19,395		)	13,139
Order backlog	—		—			—		150		(113		)	37
Total intangible assets, net	$	62,656	$	(37,076	)	$	25,580	$	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 September 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 September 30,				Nine Months Ended September 30,
(In thousands)	2018		2017		2018		2017
Cost of sales	$	18	$	54	$	91	$	128
Selling, general and administrative expenses	1,770		1,715		5,275		5,032
Total amortization expense	$	1,788	$	1,769	$	5,366	$	5,160

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



(In thousands)
2018 (remaining 3 months)	$	1,778
2019	7,018
2020	5,883
2021	2,325
2022	2,216
Thereafter	6,360
Total	$	25,580