4. Patents

6 Months Ended

Jun. 30, 2019

Goodwill and Intangible Assets Disclosure [Abstract]

Patents

4. PATENTS

Acacia’s only identifiable intangible assets at June 30, 2019 and December 31, 2018 are patents and patent rights. Patent-related accumulated amortization totaled $321,054,000 and $319,580,000 as of June 30, 2019 and December 31, 2018, respectively. Acacia’s patents have remaining estimated economic useful lives ranging from ten to sixty 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 June 30, 2019:

For the years ending December 31,
	(In thousands)
	Remainder of 2019	$	1,720
	2020		2,555
	2021		1,695
	2022		1,695
	2023		1,620
	Thereafter		249
		$	9,534