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Short-Term Investments - Schedule of Cost, Gross Unrealized Holding Gains, Gross Unrealized Holding Losses and Fair Value of Available for Sale Investments (Details) - USD ($)
$ in Thousands
Jun. 30, 2021
Dec. 31, 2020
Schedule Of Available For Sale Securities [Line Items]    
Amortized Cost $ 90,987 $ 215,185
Unrealized Gains 3  
Unrealized Losses   (31)
Estimated Fair Value 90,990 215,154
U.S. Treasury Securities    
Schedule Of Available For Sale Securities [Line Items]    
Amortized Cost 90,987 215,185
Unrealized Gains 3  
Unrealized Losses   (31)
Estimated Fair Value $ 90,990 $ 215,154