Quarterly report pursuant to Section 13 or 15(d)

Credit Losses - Schedule of Fair Value and Unrealized Losses on Available for Sale Debt Securities (Detail)

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Credit Losses - Schedule of Fair Value and Unrealized Losses on Available for Sale Debt Securities (Detail) - USD ($)
$ in Thousands
Jul. 31, 2021
Apr. 30, 2021
Commercial Paper    
Fair Value And Unrealized Losses On Available For Sale Debt Securities [Line Items]    
Less Than 12 Months, Fair Value $ 21,879 $ 36,378
Less Than 12 Months, Unrealized Loss 6 7
Commercial Paper | Cash and Cash Equivalents    
Fair Value And Unrealized Losses On Available For Sale Debt Securities [Line Items]    
Fair Value   5,749
Commercial Paper | Marketable Securities Current    
Fair Value And Unrealized Losses On Available For Sale Debt Securities [Line Items]    
Available For Sale Securities Debt Securities, Current 21,879 30,629
Corporate Notes/Bonds    
Fair Value And Unrealized Losses On Available For Sale Debt Securities [Line Items]    
Less Than 12 Months, Fair Value 31,082 26,350
Less Than 12 Months, Unrealized Loss 19 20
Corporate Notes/Bonds | Marketable Securities Current    
Fair Value And Unrealized Losses On Available For Sale Debt Securities [Line Items]    
Available For Sale Securities Debt Securities, Current 17,087 10,133
Corporate Notes/Bonds | Marketable Securities Non-Current    
Fair Value And Unrealized Losses On Available For Sale Debt Securities [Line Items]    
Available For Sale Securities Debt Securities, Non-Current $ 13,995 $ 16,217