6. Intangible assets, net

Intangible assets other than goodwill consist of the following:


(In thousands)	Amortization period	March 31, 2016			December 31, 2015
Gross amount:
Purchased IP and capitalized litigation costs	10 years	$	2,700		$	1,659
Software developed for internal use	3-10 years		4,845			2,571
Developed technology	5 years		10,716			10,716
Customer relationships	7 years		30,875			30,875
Trademarks	20 years		16,357			16,357
Domain names	20 years		191			191
Databases	10 years		25,052			25,052
Non-competition agreements	5 years		728			728
			91,464			88,149
Accumulated amortization:
Purchased IP and capitalized litigation costs			(41	)		(34	)
Software developed for internal use			(62	)		(50	)
Developed technology			(668	)		(133	)
Customer relationships			(1,375	)		(272	)
Trademarks			(255	)		(50	)
Domain names			(3	)		(1	)
Databases			(781	)		(155	)
Non-competition agreements			(45	)		(9	)
			(3,230	)		(704	)
Net intangible assets:
Purchased IP and capitalized litigation costs			2,659			1,625
Software developed for internal use			4,783			2,521
Developed technology			10,048			10,583
Customer relationships			29,500			30,603
Trademarks			16,102			16,307
Domain names			188			190
Databases			24,271			24,897
Non-competition agreements			683			719
		$	88,234		$	87,445

The amount associated with Purchased IP and capitalized litigation costs is mainly related to the intellectual property purchased by TBO from Ole Poulsen (“Purchased IP”) pursuant to the Intellectual Property Purchase Agreement dated October 14, 2014 (“IP Agreement”) and related legal and other costs incurred in defending the Company’s claims to the Purchased IP. The gross amount associated with software developed for internal use mainly represent capitalized costs of internally developed software. The amounts relating to developed technology, customer relationships, trademarks, domain names, databases, and non-competition agreements all represent the fair values of intangible assets acquired as a result of the Fluent Acquisition.

Amortization expenses of $2,526 and $12 were included in depreciation and amortization expenses for the three months ended March 31, 2016 and 2015, respectively. As of March 31, 2016, there were intangible assets of $2,425 and $4,365, included into the gross amounts of Purchased IP and capitalized litigation costs, and software developed for internal use, respectively, that have not started amortization. These intangible assets will start to amortize when they are put into use.

The Company capitalized $3,315 during the three months ended March 31, 2016, with $1,041 related to Purchased IP litigation costs and $2,274 related to internally developed software.

As of March 31, 2016, estimated amortization expenses related to the Company’s intangible assets for the remainder of 2016 through 2020 and thereafter are as follows:

(In thousands)
Year	March 31, 2016
Remainder of 2016	$	7,951
2017		10,853
2018		10,853
2019		10,782
2020		10,617
2021 and thereafter		37,178
	$	88,234