Intangible Assets

3 Months Ended

Mar. 31, 2019

Intangible Assets Net Excluding Goodwill [Abstract]

11. INTANGIBLE ASSETS

Intangible assets include intangibles acquired in conjunction with several acquisitions since 2011, with the most recent being SmartRG, Inc. in November 2018 and SEI’s North American EPON business and technology license and OEM supply agreement with SEI in March 2018.

The following table presents our intangible assets as of March 31, 2019 and December 31, 2018:

	March 31, 2019							December 31, 2018
(In thousands)	Gross Value		Accumulated Amortization			Net Value		Gross Value		Accumulated Amortization			Net Value
Customer relationships	$	22,363	$	(5,797	)	$	16,566	$	22,455	$	(5,380	)	$	17,075
Developed technology		10,170		(2,526	)		7,644		12,801		(4,867	)		7,934
Licensed technology		5,900		(683	)		5,217		5,900		(520	)		5,380
Supplier relationships		2,800		(1,458	)		1,342		2,800		(1,108	)		1,692
Licensing agreements		560		(24	)		536		560		(5	)		555
Patents		500		(174	)		326		500		(157	)		343
Trade names		310		(124	)		186		310		(106	)		204
Total	$	42,603	$	(10,786	)	$	31,817	$	45,326	$	(12,143	)	$	33,183

Amortization expense was $1.3 million and $0.4 million for the three months ended March 31, 2019 and 2018 respectively.

As of March 31, 2019, the estimated future amortization expense of our intangible assets is as follows:

(In thousands)	Amount
Remainder of 2019	$	3,994
2020		4,444
2021		4,096
2022		3,472
2023		3,320
Thereafter		12,491
Total	$	31,817