Intangible assets, net

Intangible assets, net, other than goodwill, consist of the following:

(In thousands)	Amortization period (years)		December 31, 2019			December 31, 2018
Gross amount:
Software developed for internal use		3	$	4,866		$	3,037
Acquired proprietary technology		4-5		13,661			11,459
Customer relationships		6-10		37,286			34,986
Trade names		4-20		16,657			16,357
Domain names		20		191			191
Databases		5-10		31,292			31,292
Non-competition agreements		2-5		1,768			1,768
				105,721			99,090
Accumulated amortization:
Software developed for internal use				(1,995	)		(1,282	)
Acquired proprietary technology				(9,516	)		(6,987	)
Customer relationships				(19,396	)		(14,417	)
Trade names				(3,359	)		(2,504	)
Domain names				(39	)		(29	)
Databases				(14,182	)		(10,573	)
Non-competition agreements				(1,631	)		(1,486	)
				(50,118	)		(37,278	)
Net intangible assets:
Software developed for internal use				2,871			1,755
Acquired proprietary technology				4,145			4,472
Customer relationships				17,890			20,569
Trade names				13,298			13,853
Domain names				152			162
Databases				17,110			20,719
Non-competition agreements				137			282
			$	55,603		$	61,812

The gross amounts associated with software developed for internal use primarily represent capitalized costs of internally developed software. The amounts relating to acquired proprietary technology, customer relationships, trade names, domain names, databases and non-competition agreements primarily represent the fair values of intangible assets acquired as a result of the acquisition of Fluent, LLC, effective

December 8, 2015 (

the "Fluent Acquisition"), the acquisition of Q Interactive, LLC, effective

June 8, 2016 (

the "Q Interactive Acquisition") and the acquisition of substantially all the assets of AdParlor Holdings, Inc. and certain of its affiliates, effective

July 1, 2019 (

as further discussed in Note

15,

Business acquisition

For the years ended

December 31, 2019

and

2018

, amortization expenses related to intangible assets, and included in depreciation and amortization expenses in the Company's consolidated statements of operations, were

$13,197

and

$12,684

, respectively.

For the years ended

December 31, 2019

and

2018

, the Company capitalized

$2,713

and

$1,659

, respectively, most of which was related to internally developed software, and wrote off

$425

and

$1,517

, respectively, due to abandonment of certain internally developed software whose net carrying values were

not

recoverable. In addition, the Company recorded

4,700

for the year ended

December 31, 2019

related to the AdParlor Acquisition.

As of

December 31, 2019

, estimated amortization expenses related to the Company’s intangible assets for

2020

through

2025

and thereafter are as follows:

(In thousands)
Year	December 31, 2019
2020	$	13,698
2021		10,885
2022		9,521
2023		4,718
2024		4,350
2025 and thereafter		12,431
Total	$	55,603