Fair Value Measurements - Fair Value of Available-for-Sale Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Jul. 31, 2021	Aug. 01, 2020
Debt Securities, Available-for-sale [Line Items]
One Year or Less	$ 101,546	$ 143,037
Over One Year Through Five Years	59,035	95,097
Over Five Years	0	0
Fair Value	160,581	238,134
U.S. Treasury securities
Debt Securities, Available-for-sale [Line Items]
One Year or Less	41,633	38,794
Over One Year Through Five Years	411	29,056
Over Five Years	0	0
Fair Value	42,044	67,850
Certificates of deposit
Debt Securities, Available-for-sale [Line Items]
One Year or Less	1,500	6,150
Over One Year Through Five Years	0	0
Over Five Years	0	0
Fair Value	1,500	6,150
Commercial paper
Debt Securities, Available-for-sale [Line Items]
One Year or Less	10,192	35,331
Over One Year Through Five Years	0	0
Over Five Years	0	0
Fair Value	10,192	35,331
Asset-backed securities
Debt Securities, Available-for-sale [Line Items]
One Year or Less	29	6,657
Over One Year Through Five Years	10,373	38,603
Over Five Years	0	0
Fair Value	10,402	45,260
Corporate bonds
Debt Securities, Available-for-sale [Line Items]
One Year or Less	48,192	56,105
Over One Year Through Five Years	48,251	27,438
Over Five Years	0	0
Fair Value	$ 96,443	$ 83,543

Debt Securities, Available-for-sale, Maturity, Allocated And Single Maturity Date, After Five Years, Fair Value

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- Definition

Fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in second through fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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-Section 50
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-URI http://asc.fasb.org/extlink&oid=123599081&loc=SL120269850-112803

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- Definition

Fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 320
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-Paragraph 3A
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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- Definition

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

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 45
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-URI http://asc.fasb.org/extlink&oid=124258926&loc=SL82898722-210454

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

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