Summary of Significant Accounting Policies - Schedule of Cash Equivalents and Marketable Securities Measured at Fair Value (Detail) - USD ($) $ in Thousands	Apr. 30, 2022	Apr. 30, 2021
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	$ 13,735	$ 2,985
Marketable securities	135,470	198,337
Cash equivalents and marketable securities	149,205	201,322
Level 1 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	13,735	2,985
Cash equivalents and marketable securities	13,735	2,985
Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents and marketable securities	135,470	198,337
Corporate Debt Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities	112,005	157,873
Corporate Debt Securities [Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities	112,005	157,873
U.S. Government Agency Securities [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities	23,465	40,464
U.S. Government Agency Securities [Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities	$ 23,465	$ 40,464