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Fair Value Measurements - Additional Information (Details) - USD ($)
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Fair Value Disclosures [Abstract]    
Financial instruments transferred among fair value hierarchy levels $ 0  
Cash equivalents included of available-for-sale securities 55,900,000 $ 15,000,000.0
Available for sale securities with contractual maturities of three months to one year. $ 103,400,000 279,700,000
Available for sale securities with contractual maturities greater than one year   $ 39,400,000