Annual report pursuant to Section 13 and 15(d)

Marketable Securities and Fair Value Measurements - Financial Assets at Fair Value on Recurring Basis (Detail)

v3.20.4
Marketable Securities and Fair Value Measurements - Financial Assets at Fair Value on Recurring Basis (Detail) - USD ($)
$ in Thousands
Dec. 31, 2020
Dec. 31, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable securities $ 92,460 $ 125,505
Cash and cash equivalents 25,218 85,451
Marketable securities, current 68,667 39,633
Marketable securities, non-current   1,510
Cash Equivalents    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Cash and cash equivalents 23,793 84,362
Money Market Funds    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable securities 23,794 79,970
Commercial Paper    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable securities 42,863 20,436
United States Treasury Bills    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable securities 21,794 16,738
United States Government-Related Debt Securities    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable securities 4,009 7,010
Corporate Bonds    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable securities   1,351
Basis of Fair Value Measurements, Level 1    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable securities 23,794 79,970
Basis of Fair Value Measurements, Level 1 | Money Market Funds    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable securities 23,794 79,970
Basis of Fair Value Measurements, Level 1 | Commercial Paper    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable securities 0 0
Basis of Fair Value Measurements, Level 1 | United States Treasury Bills    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable securities 0 0
Basis of Fair Value Measurements, Level 1 | United States Government-Related Debt Securities    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable securities 0 0
Basis of Fair Value Measurements, Level 1 | Corporate Bonds    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable securities   0
Basis of Fair Value Measurements, Level 2    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable securities 68,666 45,535
Basis of Fair Value Measurements, Level 2 | Money Market Funds    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable securities 0 0
Basis of Fair Value Measurements, Level 2 | Commercial Paper    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable securities 42,863 20,436
Basis of Fair Value Measurements, Level 2 | United States Treasury Bills    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable securities 21,794 16,738
Basis of Fair Value Measurements, Level 2 | United States Government-Related Debt Securities    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable securities 4,009 7,010
Basis of Fair Value Measurements, Level 2 | Corporate Bonds    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable securities   1,351
Basis of Fair Value Measurements, Level 3    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable securities 0 0
Basis of Fair Value Measurements, Level 3 | Money Market Funds    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable securities 0 0
Basis of Fair Value Measurements, Level 3 | Commercial Paper    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable securities 0 0
Basis of Fair Value Measurements, Level 3 | United States Treasury Bills    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable securities 0 0
Basis of Fair Value Measurements, Level 3 | United States Government-Related Debt Securities    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable securities $ 0 0
Basis of Fair Value Measurements, Level 3 | Corporate Bonds    
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable securities   $ 0