Credit Losses - Schedule of Fair Value and Unrealized Losses on Available for Sale Debt Securities (Detail) $ in Thousands	Jul. 31, 2020 USD ($)
Commercial Paper
Fair Value And Unrealized Losses On Available For Sale Debt Securities [Line Items]
Less Than 12 Months, Fair Value	$ 8,390
Less Than 12 Months, Unrealized Loss	5
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	8,390
Corporate Notes/Bonds
Fair Value And Unrealized Losses On Available For Sale Debt Securities [Line Items]
Less Than 12 Months, Fair Value	10,321
Less Than 12 Months, Unrealized Loss	3
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	$ 10,321

Fair value and unrealized losses on available for sale debt securities.

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- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), classified as current.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for less than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 7
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Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for less than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=121582814&loc=SL82922890-210455

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-Publisher FASB
-Name Accounting Standards Codification
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-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27337-111563

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