INTANGIBLE ASSETS

Intangible assets consist of the following (in thousands, except amortization period data):



	December 31,						Weighted- Average Amortization Period (in years)
	2014			2015			Weighted- Average Amortization Period (in years)
Capitalized product development cost	$	2,140		$	2,243		4
Accumulated amortization	(2,140		)	(2,172		)
Capitalized product development cost, net	—			71

Building photography	14,943			17,677			4
Accumulated amortization	(12,665		)	(15,875		)
Building photography, net	2,278			1,802

Acquired database technology	88,739			77,905			5
Accumulated amortization	(60,498		)	(62,818		)
Acquired database technology, net	28,241			15,087

Acquired customer base	199,826			221,409			10
Accumulated amortization	(102,443		)	(129,782		)
Acquired customer base, net	97,383			91,627

Acquired trade names and other intangible assets⁽¹⁾	128,171			153,910			12
Accumulated amortization	(14,451		)	(24,179		)
Acquired trade names and other intangible assets, net	113,720			129,731

Intangible assets, net	$	241,622		$	238,318

⁽¹⁾ The weighted-average amortization period for acquired trade names excludes $48.7 million for acquired trade names recorded in connection with the LoopNet acquisition on April 30, 2012, which amount is not amortized, but is subject to annual impairment tests.

Amortization expense for intangible assets was approximately $27.6 million, $55.3 million and $58.6 million for the years ended December 31, 2013, 2014 and 2015, respectively.

In the aggregate, the Company expects amortization for intangible assets existing as of December 31, 2015 for future periods to be approximately $43.0 million, $28.5 million, $20.3 million, $17.4 million and $15.8 million for the years ending December 31, 2016, 2017, 2018, 2019 and 2020, respectively.

During the fourth quarter of 2015, the Company completed the annual impairment test of the acquired trade name recorded in connection with the LoopNet acquisition and concluded that this indefinite-lived intangible asset was not impaired.

During the first quarter of 2014, the Company finalized a branding initiative plan that included, among other things, re-branding some of the services provided by its wholly owned subsidiaries, in order to better organize, update, streamline and optimize the Company’s branding strategy. The Company launched the branding initiative externally in the second quarter of 2014. Following the external launch of the branding initiative, the Company ceased using certain of its trade names. The Company evaluated these assets for impairment during the first quarter of 2014 and determined that the carrying value of trade names that the Company ceased using exceeded the fair value. The adjusted carrying value of the Company's trade name intangible assets associated with the branding initiative was amortized through the date of the external launch of the branding initiative and the fully amortized gross carrying amount was written off during the three months ended June 30, 2014.


8.	INTANGIBLE ASSETS — (CONTINUED)

During the third quarter of 2014, the Company finalized and launched a separate marketing plan that included the re-branding of a service provided by another one of its wholly owned subsidiaries, in order to provide its customers with a more enhanced experience. Following the external launch of the marketing plan, the Company ceased using one of its trade names. The Company evaluated the asset for impairment during the third quarter of 2014 and determined that the carrying value of the trade name that the Company ceased using exceeded the fair value.

As a result of these branding and marketing plans, during 2014, the Company recorded impairment charges of approximately $1.8 million in cost of revenues in the consolidated statements of operations within its North America operating segment for the year ended December 31, 2014.

In February 2015, as a result of the Company's product development efforts, it launched an improved Apartments.com website with a cleaner look, information about actual rental availabilities, rents and other fees, and better search functionality. In conjunction with the launch, the Company ceased using the database technology acquired in the acquisition of Apartments.com. The Company evaluated the acquired database technology for impairment during the first quarter of 2015 and determined that the carrying value of the acquired database technology was impaired as the Company had ceased using the asset. The Company recorded an impairment charge of approximately $1.4 million in cost of revenues in the consolidated statements of operations within the Company's North America operating segment for the year ended December 31, 2015.

In June 2015, following the June 1, 2015 acquisition of Apartment Finder, the Company decided to cease providing certain Apartment Finder services. Additionally, in June 2015, the Company decided to cease development work related to a development project within Apartment Finder. The Company evaluated the acquired customer base and acquired database technology for impairment during the second quarter of 2015 and, based on that evaluation, determined that the customer base and database technology assets associated with the ceased services and development work were impaired as they were not expected to provide any economic benefit to the Company. The Company recorded an impairment charge of approximately $1.4 million, most of which was recorded in general and administrative expenses in the consolidated statements of operations within the Company's North America operating segment for the year ended December 31, 2015.