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Fair Value Measurement - Summary of Investments Measured and Recognized at Fair Value (Details) - Fair Value, Recurring - USD ($)
$ in Thousands
Mar. 31, 2020
Dec. 31, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Amortized Cost $ 170,704 $ 200,673
Gross Unrealized Gains 312 52
Gross Unrealized Losses (107) (9)
Fair Value 170,909 200,716
U.S. Treasury Securities | Level 1    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Amortized Cost 45,242 66,244
Gross Unrealized Gains 227 48
Fair Value 45,469 66,292
Corporate Bonds | Level 2    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Amortized Cost 40,685 39,953
Gross Unrealized Gains   3
Gross Unrealized Losses (107)  
Fair Value 40,578 39,956
Commercial Paper | Level 2    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Amortized Cost 63,606 74,507
Gross Unrealized Gains 1  
Gross Unrealized Losses   (9)
Fair Value 63,607 74,498
U.S. Government Agency Securities | Level 2    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Amortized Cost 21,171 19,969
Gross Unrealized Gains 84 1
Fair Value $ 21,255 $ 19,970