Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Net loss including noncontrolling interests	$ (7,608)	$ (32,864)	$ (17,763)	$ (93,481)
Other comprehensive income (loss):
Unrealized gain on short-term investments, net of tax of $0	0	85	0	75
Unrealized loss on foreign currency translation, net of tax of $0	0	(5)	0	(109)
Total other comprehensive loss	(7,608)	(32,784)	(17,763)	(93,515)
Comprehensive (income) loss attributable to noncontrolling interests	0	(331)	14	(179)
Comprehensive loss attributable to Acacia Research Corporation	$ (7,608)	$ (33,115)	$ (17,749)	$ (93,694)