Intangible Assets

The gross carrying amount and accumulated amortization of our intangible assets, other than goodwill, are as follows:



	December 31, 2014							December 31, 2013
	Gross Assets		Accumulated Amortization			Net		Gross Assets		Accumulated Amortization			Net
	(in thousands)
Core-developed technology	$	405,434	$	(359,500	)	$	45,934	$	428,890	$	(356,017	)	$	72,873
Customer contracts and relationships	262,930		(172,755		)	90,175		291,185		(173,952		)	117,233
Trademarks and trade names	68,205		(64,905		)	3,300		73,117		(67,449		)	5,668
Other	11,579		(11,079		)	500		11,089		(11,023		)	66
Total intangible assets subject to amortization	748,148		(608,239		)	139,909		804,281		(608,441		)	195,840

A summary of the intangible asset account activity is as follows:



	Year Ended December 31,
	2014			2013
	(in thousands)
Beginning balance, intangible assets, gross	$	804,281		$	802,540
Intangible assets acquired	1,453			(1,500		)
Effect of change in exchange rates	(57,586		)	3,241
Ending balance, intangible assets, gross	$	748,148		$	804,281

Intangible assets acquired during 2014 consist of purchased technology and purchased software licenses to be sold to others. Amortization expense associated with these intangible assets is classified within Cost of revenues in the Consolidated Statements of Operations.

For the year ended December 31, 2013, the adjustment of $1.5 million to intangible assets acquired is associated with the correction of an error for a long-term revenue contract from the SmartSynch acquisition, which occurred on May 1, 2012. During the second quarter of 2013, we finalized the purchase price allocation related to this acquisition and recorded certain adjustments that are reflected as Intangible assets acquired in the table above. These adjustments primarily affected the fair value calculation of certain accrued liabilities associated with specific contracts. Among these adjustments was the correction of an error associated with a long-term revenue contract acquired from SmartSynch. In May 2013, we determined that certain manufacturing costs were not reflected in the model used to value this contract at acquisition. Once these costs were properly added to the total cost and profitability estimates, we determined the total contract would result in a loss over the contract term. Previously, we had recognized a customer relationship intangible asset of $1.5 million associated with this contract, with amortization scheduled to begin in 2014 based on the contract's original projected cash flow. Since the contract is in an overall loss position, we determined that the intangible asset had no value. We reduced the value of this intangible asset to zero with a corresponding adjustment to goodwill.

Intangible assets of our international subsidiaries are recorded in their respective functional currencies; therefore, the carrying amounts of intangible assets increase or decrease, with a corresponding change in accumulated OCI, due to changes in foreign currency exchange rates.

A summary of intangible asset amortization expense is as follows:



Amortization expense	Year Ended December 31,
	2014		2013		2012
	(in thousands)
Amortization expense	$	43,704	$	42,019	$	47,810

Estimated future annual amortization expense is as follows:



Years ending December 31,	Estimated Annual Amortization
	(in thousands)
2015	$	33,562
2016	26,522
2017	19,485
2018	13,571
2019	10,501
Beyond 2019	36,268
Total intangible assets subject to amortization	$	139,909