Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Mar. 01, 2021	Jun. 30, 2020
Document Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Document Period End Date	Dec. 31, 2020
Current Fiscal Year End Date	--12-31
Entity File Number	1-37745
Entity Registrant Name	RealNetworks, Inc.
Entity Incorporation, State or Country Code	WA
Entity Tax Identification Number	91-1628146
Entity Address, Address Line One	1501 First Avenue South, Suite 600
Entity Address, City or Town	Seattle
Entity Address, State or Province	WA
Entity Address, Postal Zip Code	98134
City Area Code	206
Local Phone Number	674-2700
Trading Symbol	RNWK
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Central Index Key	0001046327
Amendment Flag	false
Document Transition Report	false
Title of 12(g) Security	None
Entity Common Stock, Shares Outstanding		38,525,790
Entity Public Float			$ 31.0
Common Stock
Document Information [Line Items]
Title of 12(b) Security	Common Stock
Convertible Preferred Stock
Document Information [Line Items]
Title of 12(b) Security	Preferred Share Purchase Rights