Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (1,661)	$ (4,214)
Unrealized gain (loss) on investments, net of tax	32	1,045
Comprehensive income (loss)	(1,629)	(3,169)
Comprehensive loss attributable to noncontrolling interest	(1,777)	(1,411)
Total comprehensive income (loss) attributable to InterDigital, Inc.	$ 148	$ (1,758)