4. Patents

9 Months Ended

Sep. 30, 2019

Goodwill and Intangible Assets Disclosure [Abstract]

Patents

4. PATENTS

Acacia’s only identifiable intangible assets at September 30, 2019 and December 31, 2018 are patents and patent rights. Patent-related accumulated amortization totaled $321,917,000 and $319,580,000 as of September 30, 2019 and December 31, 2018, respectively. Acacia’s patents have remaining estimated economic useful lives ranging from six to fifty seven months. The weighted-average remaining estimated economic useful life of Acacia’s patents is approximately four years.

The following table presents the scheduled annual aggregate amortization expense as of September 30, 2019:

For the years ending December 31,
(In thousands)
Remainder of 2019	$	857
2020		2,555
2021		1,695
2022		1,695
2023		1,620
Thereafter		249
	$	8,671