Financial Instruments and Fair Value - Schedule of Fair Value of Financial Instruments Measured on Recurring Basis (Detail) - USD ($)
$ in Thousands
Jan. 31, 2022
Jan. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable debt securities $ 20 $ 214,802
Money market funds [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable debt securities 20 171
Commercial paper [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable debt securities 0 66,181
Corporate bonds [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable debt securities 0 103,081
Asset-backed securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable debt securities 0 15,904
U.S. government securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable debt securities 0 29,465
Level 1 [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable debt securities 20 171
Level 1 [Member] | Money market funds [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable debt securities 20 171
Level 1 [Member] | Commercial paper [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable debt securities 0 0
Level 1 [Member] | Corporate bonds [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable debt securities 0 0
Level 1 [Member] | Asset-backed securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable debt securities 0 0
Level 1 [Member] | U.S. government securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable debt securities 0 0
Level 2 [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable debt securities 0 214,631
Level 2 [Member] | Money market funds [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable debt securities 0 0
Level 2 [Member] | Commercial paper [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable debt securities 0 66,181
Level 2 [Member] | Corporate bonds [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable debt securities 0 103,081
Level 2 [Member] | Asset-backed securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable debt securities 0 15,904
Level 2 [Member] | U.S. government securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable debt securities 0 29,465
Level 3 [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable debt securities 0 0
Level 3 [Member] | Money market funds [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable debt securities 0 0
Level 3 [Member] | Commercial paper [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable debt securities 0 0
Level 3 [Member] | Corporate bonds [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable debt securities 0 0
Level 3 [Member] | Asset-backed securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable debt securities 0 0
Level 3 [Member] | U.S. government securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total cash equivalents and marketable debt securities $ 0 $ 0