Fair Value Measurements - Schedule of Fair Value Measurements (Details) - USD ($) $ in Thousands	Oct. 31, 2021	Jan. 31, 2021
Assets, Fair Value Disclosure
Cash equivalents	$ 721,877	$ 683,101
Short-term investments	2,955,613	3,087,887
Long-term investments	1,211,858	1,165,275
Money market funds
Assets, Fair Value Disclosure
Cash equivalents	581,689	334,891
U.S. government and agency securities
Assets, Fair Value Disclosure
Cash equivalents	60,000	23,700
Commercial paper
Assets, Fair Value Disclosure
Cash equivalents	46,993	242,037
Certificates of deposit
Assets, Fair Value Disclosure
Cash equivalents	27,002	23,503
Corporate notes and bonds
Assets, Fair Value Disclosure
Cash equivalents	6,193	58,970
Recurring
Assets, Fair Value Disclosure
Total	4,889,348	4,936,263
Recurring \| Corporate notes and bonds
Assets, Fair Value Disclosure
Short-term investments	1,454,923	1,318,573
Long-term investments	1,054,854	968,580
Recurring \| Commercial paper
Assets, Fair Value Disclosure
Short-term investments	1,065,978	711,372
Recurring \| U.S. government and agency securities
Assets, Fair Value Disclosure
Cash equivalents		23,700
Short-term investments	243,323	829,318
Long-term investments	148,013	186,945
Recurring \| Certificates of deposit
Assets, Fair Value Disclosure
Short-term investments	191,389	228,624
Long-term investments	8,991	9,750
Recurring \| Money market funds
Assets, Fair Value Disclosure
Cash equivalents	581,689	334,891
Recurring \| U.S. government and agency securities
Assets, Fair Value Disclosure
Cash equivalents	60,000
Recurring \| Commercial paper
Assets, Fair Value Disclosure
Cash equivalents	46,993	242,037
Recurring \| Certificates of deposit
Assets, Fair Value Disclosure
Cash equivalents	27,002	23,503
Recurring \| Corporate notes and bonds
Assets, Fair Value Disclosure
Cash equivalents	6,193	58,970
Recurring \| Level 1
Assets, Fair Value Disclosure
Total	581,689	334,891
Recurring \| Level 1 \| Corporate notes and bonds
Assets, Fair Value Disclosure
Short-term investments	0	0
Long-term investments	0	0
Recurring \| Level 1 \| Commercial paper
Assets, Fair Value Disclosure
Short-term investments	0	0
Recurring \| Level 1 \| U.S. government and agency securities
Assets, Fair Value Disclosure
Cash equivalents		0
Short-term investments	0	0
Long-term investments	0	0
Recurring \| Level 1 \| Certificates of deposit
Assets, Fair Value Disclosure
Short-term investments	0	0
Long-term investments	0	0
Recurring \| Level 1 \| Money market funds
Assets, Fair Value Disclosure
Cash equivalents	581,689	334,891
Recurring \| Level 1 \| U.S. government and agency securities
Assets, Fair Value Disclosure
Cash equivalents	0
Recurring \| Level 1 \| Commercial paper
Assets, Fair Value Disclosure
Cash equivalents	0	0
Recurring \| Level 1 \| Certificates of deposit
Assets, Fair Value Disclosure
Cash equivalents	0	0
Recurring \| Level 1 \| Corporate notes and bonds
Assets, Fair Value Disclosure
Cash equivalents	0	0
Recurring \| Level 2
Assets, Fair Value Disclosure
Total	4,307,659	4,601,372
Recurring \| Level 2 \| Corporate notes and bonds
Assets, Fair Value Disclosure
Short-term investments	1,454,923	1,318,573
Long-term investments	1,054,854	968,580
Recurring \| Level 2 \| Commercial paper
Assets, Fair Value Disclosure
Short-term investments	1,065,978	711,372
Recurring \| Level 2 \| U.S. government and agency securities
Assets, Fair Value Disclosure
Cash equivalents		23,700
Short-term investments	243,323	829,318
Long-term investments	148,013	186,945
Recurring \| Level 2 \| Certificates of deposit
Assets, Fair Value Disclosure
Short-term investments	191,389	228,624
Long-term investments	8,991	9,750
Recurring \| Level 2 \| Money market funds
Assets, Fair Value Disclosure
Cash equivalents	0	0
Recurring \| Level 2 \| U.S. government and agency securities
Assets, Fair Value Disclosure
Cash equivalents	60,000
Recurring \| Level 2 \| Commercial paper
Assets, Fair Value Disclosure
Cash equivalents	46,993	242,037
Recurring \| Level 2 \| Certificates of deposit
Assets, Fair Value Disclosure
Cash equivalents	27,002	23,503
Recurring \| Level 2 \| Corporate notes and bonds
Assets, Fair Value Disclosure
Cash equivalents	$ 6,193	$ 58,970

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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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), classified as current.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-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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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 noncurrent.

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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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