Patents

12 Months Ended

Dec. 31, 2018

Acacia’s only identifiable intangible assets are patents and patent rights, with estimated remaining economic useful lives ranging from one to five 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 investments in intangible assets as of December 31, 2018 and 2017 are as follows (in thousands):



	2018			2017

Gross carrying amount - patents	$	326,167		$	444,137
Accumulated amortization - patents⁽¹⁾	(319,580		)	(382,220		)
Patents, net	$	6,587		$	61,917

⁽¹⁾ Includes patent impairment charges for the applicable periods.

The weighted-average remaining estimated economic useful life of Acacia’s patents and patent rights is 4 years. Scheduled annual aggregate amortization expense is estimated to be $2,559,000 in fiscal year 2019, $1,671,000 in 2020, $811,000 in 2021, $811,000 in 2022 and $735,000 in 2023.

Acacia recorded impairment of patent-related intangible asset charges totaling $28,210,000 and $2,248,000 for the years ended December 31, 2018 and 2017, respectively. The impairment charges related to impairments of patent portfolios due to a reduction in expected estimated future net cash flows and certain patent portfolios that management determined it would no longer allocate future resources to in connection with the licensing and enforcement of such portfolios, due primarily to adverse litigation outcomes, potential prior art related complexities 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 for the periods presented consisted of the excess of the asset’s carrying value over its estimated fair value.

For the year ended December 31, 2018, 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 $8,307,000. For the year ended December 31, 2017, there were no terminations or sales of patent portfolios.

For the years ended December 31, 2018 and 2017, capitalized patent costs, accumulated amortization and impairment charges, and sales proceeds related to patent-related sales and disposals are as follows (in thousands):



	2018		2017

Capitalized patent costs	$	117,970	$	—
Accumulated amortization / impairment charges	109,663		—
Sales proceeds	14,500		—