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Fair Value Measurements - Additional Information (Details) - USD ($)
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Fair Value Disclosures [Abstract]      
Fair value assets transferred from level 1 to level 2 $ 0 $ 0  
Fair value assets transferred from level 2 to level 1 0 0  
Fair value liabilities transferred from level 1 to level 2 0 0  
Fair value liabilities transferred from level 2 to level 1 0 0  
Fair value assets transferred into level 3 0 0  
Fair value assets transferred out of level 3 0 0  
Fair value liabilities transferred into level 3 0 0  
Fair value liabilities transferred out of level 3 0 0  
Realized gains (loss) on sale or maturity of available-for-sale marketable securities   0 $ 0
Reclassification out of accumulated other comprehensive loss $ 0 $ 0 $ 0