8. Intangible assets, net

Intangible assets other than goodwill consist of the following:

(In thousands)	Amortization period	December 31, 2016			December 31, 2015
Gross amount:
Purchased IP and capitalized litigation costs	10 years	$	-		$	1,659
Software developed for internal use	3-10 years		11,438			2,571
Acquired proprietary technology	5 years		13,532			10,716
Customer relationships	7-10 years		34,986			30,875
Trade names	20 years		18,057			16,357
Domain names	20 years		191			191
Databases	5-10 years		31,292			25,052
Non-competition agreements	2-5 years		1,768			728
			111,264			88,149
Accumulated amortization:
Purchased IP and capitalized litigation costs			-			(34	)
Software developed for internal use			(505	)		(50	)
Acquired proprietary technology			(2,660	)		(133	)
Customer relationships			(4,840	)		(272	)
Trade names			(916	)		(50	)
Domain names			(10	)		(1	)
Databases			(3,354	)		(155	)
Non-competition agreements			(448	)		(9	)
			(12,733	)		(704	)
Net intangible assets:
Purchased IP and capitalized litigation costs			-			1,625
Software developed for internal use			10,933			2,521
Acquired proprietary technology			10,872			10,583
Customer relationships			30,146			30,603
Trade names			17,141			16,307
Domain names			181			190
Databases			27,938			24,897
Non-competition agreements			1,320			719
		$	98,531		$	87,445

The amount associated with Purchased IP and capitalized litigation costs, included in the Information Services segment, is mainly related to the intellectual property purchased by the Company’s subsidiary, TBO, from Ole Poulsen (“Purchased IP”) pursuant to the Intellectual Property Purchase Agreement dated October 14, 2014 and related legal and other costs incurred and paid in defending the Company’s claims to the Purchased IP against TransUnion Risk and Alternative Data Solutions, Inc. (“TRADS”). In 2016, the Company wrote off the remaining balance of Purchased IP and capitalized litigation costs of $4,055, which is reflected in the operating expenses as write-off of intangible assets in the consolidated statements of operations for the year ended December 31, 2016, as a result of an unfavorable ruling in relation to the litigation. See Note 18, “Commitment and contingencies,” for additional information regarding the litigation involving the Purchased IP.

The gross amount associated with software developed for internal use mainly represents capitalized costs of internally developed software. The amounts relating to acquired proprietary technology, customer relationships, trade names, domain names, databases, and non-competition agreements all represent the fair values of intangible assets acquired as a result of the Fluent Acquisition and the Q Interactive Acquisition.

Amortization expenses of $12,084, $698 and $6 were included in depreciation and amortization expenses for the years ended December 31, 2016, 2015 and 2014, respectively. As of December 31, 2016, intangible assets of $4,576, included in the gross amounts of software developed for internal use, have not started amortization, as they have not yet been put into use.

The Company capitalized $11,318 and $3,428 during the years ended December 31, 2016 and 2015, with $8,867 and $2,230 related to internally developed software, and $2,451 and $1,198 related to purchased intellectual property litigation costs, respectively.

As of December 31, 2016, estimated amortization expenses related to the Company’s intangible assets for 2017 through 2022 and thereafter are as follows:

(In thousands)
Year	December 31, 2016
2017	$	13,860
2018		13,901
2019		13,592
2020		13,150
2021		9,942
2022 and thereafter		34,086
Total	$	98,531