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Marketable Securities - Additional Information (Details) - USD ($)
3 Months Ended 9 Months Ended
Sep. 30, 2020
Sep. 30, 2020
Dec. 31, 2019
Investments Debt And Equity Securities [Abstract]      
Marketable securities     $ 0
Sale of marketable securities $ 0 $ 0  
Aggregate fair value of securities, unrealized loss position $ 0 0  
Securities with other-than-temporary impairment   $ 0