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
	Mar. 31, 2019	Mar. 31, 2018
Earnings Per Share [Abstract]
Net income (loss) attributable to RealNetworks	$ 1,533	$ (5,178)
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	1,472	(4,908)
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	1,214	(5,178)
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	$ 1,446	$ (4,781)
Weighted average common shares outstanding used to compute basic EPS	37,820	37,449
Dilutive effect of stock based awards	92	0
Weighted average common shares outstanding used to compute diluted EPS	37,912	37,449
Earnings Per Share, Basic	$ 0.04	$ (0.14)
Earnings Per Share, Diluted	$ 0.04	$ (0.14)