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Fair Value Measurements and Marketable Debt Securities - Summary of Marketable Debt Securities (Detail) - USD ($)
$ in Thousands
Mar. 31, 2020
Dec. 31, 2019
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost $ 24,873 $ 43,015
Gross Unrealized Gains 36 35
Gross Unrealized Losses (4)  
Fair Value 24,905 43,050
Corporate Bonds (Due within 1 Year) [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 8,590 14,628
Gross Unrealized Gains 3 20
Gross Unrealized Losses (4)  
Fair Value 8,589 14,648
Commercial Paper (Due within 1 Year) [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 5,687 13,406
Fair Value 5,687 13,406
U.S. Government Securities (Due within 1 Year) [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Amortized Cost 10,596 14,981
Gross Unrealized Gains 33 15
Fair Value $ 10,629 $ 14,996