Goodwill and Intangible Assets, Net

Goodwill

Changes in the carrying amount of goodwill were as follows:



(In thousands)
Balance at December 31, 2018	$	48,485
Foreign exchange effects	(13		)
Balance at June 30, 2019	$	48,472

Intangible Assets, Net

The components of intangible assets, net were as follows:



	June 30, 2019							December 31, 2018
(In thousands)	Gross ⁽¹⁾		Accumulated Amortization ⁽¹⁾			Net		Gross ⁽¹⁾		Accumulated Amortization ⁽¹⁾			Net
Distribution rights	$	326	$	(199	)	$	127	$	329	$	(188	)	$	141
Patents	15,254		(6,041		)	9,213		14,560		(5,704		)	8,856
Trademarks and trade names	2,786		(2,053		)	733		2,786		(1,900		)	886
Developed and core technology	12,560		(9,095		)	3,465		12,560		(8,087		)	4,473
Capitalized software development costs	288		—			288		155		—			155
Customer relationships	32,684		(24,464		)	8,220		32,534		(22,675		)	9,859
Total intangible assets, net	$	63,898	$	(41,852	)	$	22,046	$	62,924	$	(38,554	)	$	24,370


⁽¹⁾	This table excludes the gross value of fully amortized intangible assets totaling $7.2 million and $7.1 million at June 30, 2019 and December 31, 2018, respectively.

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



	Three Months Ended June 30,				Six Months Ended June 30,
(In thousands)	2019		2018		2019		2018
Cost of sales	$	—	$	18	$	—	$	73
Selling, general and administrative expenses	1,800		1,758		3,584		3,505
Total amortization expense	$	1,800	$	1,776	$	3,584	$	3,578

Estimated future annual amortization expense related to our intangible assets at June 30, 2019, was as follows:



(In thousands)
2019 (remaining 6 months)	$	3,635
2020	6,137
2021	2,575
2022	2,354
2023	2,209
Thereafter	5,136
Total	$	22,046