Fair Value Measurements - Additional Information (Detail) - USD ($) $ in Thousands, shares in Millions	3 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Mar. 31, 2020
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Unrestricted Cash And Cash Equivalents Minimum Amount Required		$ 1,500
Cash received for future issuance of equity			$ 2,100
Contingent Consideration Settlement, Cash	$ 2,500
Contingent Consideration Settlement, Shares	47.8
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability		$ (1,040)		$ (300)
Equity Unit Purchase Agreements
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Unobservable Measurement Input, Uncertainty, Description		In the third quarter of 2020, Scener, our non-wholly owned subsidiary, received $2.1 million in cash in exchange for the issuance of convertible securities, each a Simple Agreement for Future Equity. The conversion of these securities, or SAFE Notes, is contingent upon the occurrence of specific future capital-raising events by Scener. The future contingent events also contemplate the possibility of Scener having to pay back the original cash investment to each investor. The SAFE Notes are recorded as a liability on our consolidated financial statements within Other long-term liabilities and are required to be recorded at fair value each quarter. The valuation analysis model for the fair value of the SAFE Notes as of March 31, 2021 and December 31, 2020 used significant unobservable inputs that reflect our own estimates of assumptions that market participants would use. There has been no significant change in the estimated fair value since the issuance in the third quarter of 2020. Significant unobservable inputs to the valuation analysis model include the underlying conversion date for the SAFE Notes, Scener's capitalization prior to conversion of the SAFE Notes, an 80% discount rate as defined in the SAFE Note agreements, conversion price, conversion shares and an annual present value rate. All of the inputs are subject to significant judgment. Based on Scener's outstanding shares, without regard to potential dilution by the SAFE Notes or any other convertible securities, RealNetworks owns 82% of Scener. See Note 13. Related Party Transactions for additional discussion of Scener.
Equity Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Unobservable Measurement Input, Uncertainty, Description		Investments as of March 31, 2021 and December 31, 2020 are comprised of Napster Group ordinary shares received as a portion of the consideration from the Napster disposition, which closed on December 30, 2020. The fair value of these equity securities was calculated using the closing price of the shares as of March 31, 2021 and December 31, 2020 and discounted for a lack of liquidity due to the 12-month contractual restriction on selling or transferring the shares, subject to certain exceptions. The determination of the discount required the use of significant unobservable inputs, such as the lock-up period combined with an estimated equity volatility for the shares, that reflect our own estimates of assumptions that market participants would use. A 10% increase or decrease to the equity volatility rate could result in a $0.1 million decrease or increase, respectively, in the fair value of the stock. For the three months ended March 31, 2021, we recognized unrealized losses of $4.3 million in Loss on equity and other investments, net on the condensed consolidated statements of operations.
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		$ (4,300)