v3.20.1
Investments and Fair Value Measurement - Summary of Amortized Cost, Unrealized Gains and Losses of Financial Assets (Details) - USD ($)
$ in Thousands
Mar. 31, 2020
Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost $ 2,281,000 $ 2,279,000
Allowance for Credit Loss (173,000) 0
Recurring    
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost 3,341,000 2,894,000
Unrealized Gains 0 61,000
Unrealized Losses (25,000) 0
Allowance for Credit Loss (173,000)  
Fair Value 3,143,000 2,955,000
Recurring | Commercial paper    
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost 355,000 233,000
Unrealized Gains 0 0
Unrealized Losses 0 0
Allowance for Credit Loss 0  
Fair Value 355,000 233,000
Recurring | U.S. government and agency securities    
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost 269,000 153,000
Unrealized Gains 0 0
Unrealized Losses 0 0
Allowance for Credit Loss 0  
Fair Value 269,000 153,000
Recurring | Corporate bonds    
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost 405,000 199,000
Unrealized Gains 0 0
Unrealized Losses (2,000) 0
Allowance for Credit Loss 0  
Fair Value 403,000 199,000
Recurring | Non-marketable debt securities    
Debt Securities, Available-for-sale [Line Items]    
Amortized Cost 2,312,000 2,309,000
Unrealized Gains 0 61,000
Unrealized Losses (23,000) 0
Allowance for Credit Loss (173,000)  
Fair Value $ 2,116,000 $ 2,370,000