Intangibles

The following table presents the gross carrying amount and accumulated amortization of our finite-lived intangible assets as of December 31, 2012 (in thousands):



	Gross Carrying Amount		Accumulated Amortization		Net Carrying Amount		Weighted Average Useful Life
Developed technology	$	40,200	$	21,312	$	18,888	7 years
In-process research and development	1,900		267		1,633		8 years
Customer relationships	17,600		3,225		14,375		9 years
Trademarks	5,200		818		4,382		10 years
Lease agreements	2,600		902		1,698		5 years
Total intangible assets from Vocollect acquisition:	67,500		26,524		40,976
Other intangibles	14,605		10,839		3,766		5 years
Total	$	82,105	$	37,363	$	44,742

The following table presents the gross carrying amount and accumulated amortization of our finite-lived intangible assets as of December 31, 2011 (in thousands):



	Gross Carrying Amount		Accumulated Amortization		Net Carrying Amount		Weighted Average Useful Life
Developed technology	$	40,200	$	9,416	$	30,784	5 years
In-process research and development	1,900		—		1,900		7 years
Customer relationships	17,600		623		16,977		11 years
Trademarks	5,200		303		4,897		10 years
Lease agreements	2,600		245		2,355		8 years
Total intangible assets from Vocollect acquisition:	67,500		10,587		56,913
Other intangibles	14,459		9,376		5,083		5 years
Total	$	81,959	$	19,963	$	61,996

During 2012, we performed a Step 2 goodwill impairment analysis (described in Note 15, Goodwill and Other Long-Lived Assets), which indicated the useful lives of intangible assets related to our acquisition of Vocollect had changed from our previous estimates. As a result, we changed the useful lives of the following intangible assets: developed technology, in-process research and development, customer relationships, and lease agreements.

Our intangible assets have a finite life and are amortized over their estimated useful lives on an accelerated basis determined by their estimated discounted cash flows. Amortization expense on intangible assets was $17.5 million, $11.8 million and $0.8 million for the years ended December 31, 2012, 2011 and 2010, respectively.

Estimated amortization expense for the succeeding five fiscal years is as follows (in thousands):



Year	Amount
2013	$	13,426
2014	11,814
2015	8,160
2016	4,897
2017	2,954
Beyond 2017	3,491
Total	$	44,742