Earnings (Loss) Per Share (Calculation of Basic and Diluted Earnings Per Share) (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Jun. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share [Abstract]
Net loss from continuing operations attributable to RealNetworks	$ (3,231)	$ (5,203)		$ (10,890)	$ (10,517)
Net loss from discontinued operations attributable to RealNetworks	(7)	(765)		(2,102)	(3,120)
Net loss attributable to RealNetworks	$ (3,238)	$ (5,968)	$ (9,202)	$ (12,992)	$ (13,637)
Shares used to compute basic net income (loss) per share	38,270	38,062		38,247	37,944
Dilutive effect of stock based awards	0	0		0	0
Shares used to compute diluted net income (loss) per share	38,270	38,062		38,247	37,944
Continuing operations, basic (USD per share)	$ (0.08)	$ (0.14)		$ (0.28)	$ (0.28)
Discontinued operations, basic (USD per share)	0	(0.02)		(0.06)	(0.08)
Basic net income (loss) per share (USD per share)	(0.08)	(0.16)		(0.34)	(0.36)
Continuing operations, diluted (USD per share)	(0.08)	(0.14)		(0.28)	(0.28)
Discontinued operations, diluted (USD per share)	0	(0.02)		(0.06)	(0.08)
Diluted net income (loss) per share (USD per share)	$ (0.08)	$ (0.16)		$ (0.34)	$ (0.36)