Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Revenues	$ 131,506	$ 65,402
Portfolio operations:
Inventor royalties	35,168	4,952
Contingent legal fees	31,501	16,682
Patent acquisition expenses	4,000	0
Litigation and licensing expenses - patents	8,866	18,219
Amortization of patents	27,120	22,154
General and administrative expenses (including non-cash stock compensation expense (credit) of ($317) in 2018 and $8,885 in 2017)	18,850	27,219
Impairment of Patent-Related Intangible Assets	28,210	2,248
Other	2,602	1,200
Total Portfolio Operations	137,467	65,455
Net loss	(5,961)	(53)
Operating loss	(24,811)	(27,272)
Gain on Conversion of Loan and Accrued Interest	0	2,671
Gain on exercise of Primary Warrant	0	4,616
Change in fair value of investment	(59,103)	42,239
Realized Investment Gains (Losses)	(19,095)
Income (Loss) from Equity Method Investments	0	(220)
Interest income and other	969	1,605
Total other income (expense)	(1,629)	1,000
Total other income (expense)	(78,858)	51,911
Income (loss) from operations before provision for income taxes	(103,669)	24,639
Provision for income taxes	(1,179)	(2,955)
Net income (loss) including noncontrolling interests in subsidiaries	(104,848)	21,684
Net (income) loss attributable to noncontrolling interests in subsidiaries	(181)	496
Net income (loss) attributable to Acacia Research Corporation	(105,029)	22,180
Net Loss Available to Common Stockholders, Basic and Diluted	$ (105,029)	$ 22,147
Earnings Per Share, Basic and Diluted	$ (2.10)	$ 0.44
Weighted Average Number of Shares Outstanding, Basic	49,969,062	50,495,119
Weighted Average Number of Shares Outstanding, Diluted	49,969,062	50,692,012
Common Stock [Member]
Portfolio operations:
Change in fair value of investment	$ (47,208)	$ 33,922
Realized Investment Gains (Losses)	$ (19,095)	$ 0