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Cash And Cash Equivalents, Short-Term Bank Deposits And Marketable Securities- Additional Information (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]    
Gross unrealized gains on the marketable securities $ 51.4 $ 29.0
Prepaid Expenses and Other Current Assets [Member]    
Debt Securities, Available-for-sale [Line Items]    
Interest receivable $ 19.5 $ 24.4