GOODWILL AND OTHER IDENTIFIABLE INTANGIBLE ASSETS

Acacia’s only identifiable intangible assets are patents and patent rights, with estimated remaining economic useful lives ranging from one to ten years. For all periods presented, all of Acacia’s identifiable intangible assets were subject to amortization. The gross carrying amounts and accumulated amortization related to acquired intangible assets as of December 31, 2013 and 2012 are as follows (in thousands):



	2013			2012

Gross carrying amount - patents	$	400,755		$	383,379
Accumulated amortization - patents	(112,323		)	(69,850		)
Patents, net	$	288,432		$	313,529

The weighted-average remaining estimated economic useful life of Acacia’s patents and patent rights is 7 years. Scheduled annual aggregate amortization expense for each of the next five years through December 31, 2018 is estimated to be $47,654,000 in 2014, $46,554,000 in 2015, $44,051,000 in 2016, $43,268,000 in 2017, and $39,381,000 in 2018.

For the years ended December 31, 2013, 2012 and 2011, on a consolidated basis, Acacia’s operating subsidiaries incurred and capitalized patent and patent rights acquisition costs totaling $25,061,000, $178,260,000 (excluding the acquisition of ADAPTIX) and $14,680,000, respectively. The patents have estimated economic useful lives ranging from three to ten years. Included in capitalized patent costs as of December 31, 2013 are $4,000,000 of accrued future patent-related acquisition costs that management expects to incur pursuant to the terms of the underlying patent acquisition agreements, which are being amortized over the estimated economic useful life of the patents acquired.

Refer to Note 8 to these consolidated financial statements for additions to patents and goodwill in connection with Acacia’s acquisition of ADAPTIX and the related application of the acquisition method of accounting.

During the periods presented, certain operating subsidiaries recovered up-front patent portfolio acquisition costs from applicable net licensing proceeds prior to the scheduled amortization of such up-front patent portfolio acquisition costs, resulting in the acceleration of amortization expense for the applicable patent-related assets. For the years ended December 31, 2013, 2012 and 2011, accelerated amortization expense related to the recovery of up-front patent acquisition costs totaled $592,000, $10,574,000 and $3,111,000, respectively.

For the years ended December 31, 2013, 2012 and 2011, pursuant to the terms of the respective inventor agreements, certain Acacia operating subsidiaries elected to terminate or sell their rights to patent portfolios, resulting in the acceleration of amortization expense for the patent-related assets totaling $1,747,000, $3,034,000 and $1,103,000, respectively. Included in amortization of patents for the year ended December 31, 2013 are patent impairment charges totaling $4,619,000. The impairment charges, related to certain patent portfolios that management, in the fourth quarter of 2013, determined it would no longer allocate future resources to in connection with the licensing and enforcement of such portfolios, due primarily to potential prior art related complexities in two of the programs and/or the overall determination that future resources would be allocated to other licensing and enforcement programs with higher potential return profiles. The impairment charges consisted of the remaining net carrying value of the related portfolios as of December 31, 2013.

For the years ended December 31, 2013, 2012 and 2011, capitalized patent costs and accumulated amortization, and sales proceeds and other costs, related to patent-related sales and disposals are as follows (in thousands):



	2013		2012		2011

Capitalized patent costs	$	3,500	$	5,500	$	4,612
Accumulated amortization	1,753		2,466		3,509
Sales proceeds	1,000		2,792		11,000
Other costs	—		—		4,717