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Financial Instruments - Additional Information (Details)
1 Months Ended 12 Months Ended
Jul. 05, 2019
shares
Sep. 19, 2018
shares
Jun. 30, 2020
USD ($)
shares
Jul. 31, 2019
USD ($)
Dec. 31, 2020
USD ($)
Derivative
Dec. 31, 2019
USD ($)
Derivative
Dec. 31, 2018
USD ($)
Derivative
shares
Schedule Of Investments [Line Items]              
Cash, cash equivalents and short -term investments         $ 257,100,000 $ 121,500,000  
Unrealized loss net of tax on marketable debt securities         100,000 100,000  
Impairment charges related to marketable debt securities           $ 0 $ 0
Provision for credit loss expense related available for sale debt securities         $ 0    
Derivative, number of instruments held | Derivative         0 0 0
TiVo Merger | Non-marketable Equity Securities              
Schedule Of Investments [Line Items]              
Equity securities accounted for under equity method         $ 4,200,000    
Equity securities without a readily determinable fair value         100,000    
Non-marketable equity securities, without a readily determinable fair value, impairments or adjustments         0 $ 0  
Onkyo Corporation              
Schedule Of Investments [Line Items]              
Number of common shares purchased | shares   7,000,000          
Ownership interest, percentage   6.30%          
Number of investment shares sold | shares 2,800,000   4,200,000       0
Equity securities, realized gains or losses on sales     $ 700,000 $ 900,000      
Operating Accounts              
Schedule Of Investments [Line Items]              
Cash, cash equivalents and short -term investments         $ 135,000,000.0 $ 72,000,000.0