Fair Value Measurements - Fair Value, Assets Measured on Recurring Basis (Details) - USD ($) $ in Thousands	Jan. 31, 2023	Jan. 31, 2022
Assets, Fair Value Disclosure
Cash equivalents:	$ 398,345	$ 845,230
Short-term investments	3,067,966	2,766,364
Long-term investments	1,073,023	1,256,207
Money market funds
Assets, Fair Value Disclosure
Cash equivalents:	379,094	722,492
Commercial paper
Assets, Fair Value Disclosure
Cash equivalents:	9,304	77,794
Corporate notes and bonds
Assets, Fair Value Disclosure
Cash equivalents:	6,903	7,949
Certificates of deposit
Assets, Fair Value Disclosure
Cash equivalents:	3,044
U.S. government and agency securities
Assets, Fair Value Disclosure
Cash equivalents:		36,995
Recurring
Assets, Fair Value Disclosure
Total	4,539,334	4,867,801
Recurring \| Corporate notes and bonds
Assets, Fair Value Disclosure
Short-term investments	1,301,296	1,662,436
Long-term investments	801,784	935,603
Recurring \| U.S. government and agency securities
Assets, Fair Value Disclosure
Short-term investments	440,128	116,712
Long-term investments	263,708	320,207
Recurring \| Commercial paper
Assets, Fair Value Disclosure
Short-term investments	881,348	883,636
Recurring \| Certificates of deposit
Assets, Fair Value Disclosure
Short-term investments	445,194	103,580
Long-term investments	7,531	397
Recurring \| Money market funds
Assets, Fair Value Disclosure
Cash equivalents:	379,094	722,492
Recurring \| Commercial paper
Assets, Fair Value Disclosure
Cash equivalents:	9,304	77,794
Recurring \| Corporate notes and bonds
Assets, Fair Value Disclosure
Cash equivalents:	6,903	7,949
Recurring \| Certificates of deposit
Assets, Fair Value Disclosure
Cash equivalents:	3,044
Recurring \| U.S. government and agency securities
Assets, Fair Value Disclosure
Cash equivalents:		36,995
Recurring \| Level 1
Assets, Fair Value Disclosure
Total	379,094	722,492
Recurring \| Level 1 \| Corporate notes and bonds
Assets, Fair Value Disclosure
Short-term investments	0	0
Long-term investments	0	0
Recurring \| Level 1 \| U.S. government and agency securities
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 \| 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:	379,094	722,492
Recurring \| Level 1 \| Commercial paper
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 1 \| Certificates of deposit
Assets, Fair Value Disclosure
Cash equivalents:	0
Recurring \| Level 1 \| U.S. government and agency securities
Assets, Fair Value Disclosure
Cash equivalents:		0
Recurring \| Level 2
Assets, Fair Value Disclosure
Total	4,160,240	4,145,309
Recurring \| Level 2 \| Corporate notes and bonds
Assets, Fair Value Disclosure
Short-term investments	1,301,296	1,662,436
Long-term investments	801,784	935,603
Recurring \| Level 2 \| U.S. government and agency securities
Assets, Fair Value Disclosure
Short-term investments	440,128	116,712
Long-term investments	263,708	320,207
Recurring \| Level 2 \| Commercial paper
Assets, Fair Value Disclosure
Short-term investments	881,348	883,636
Recurring \| Level 2 \| Certificates of deposit
Assets, Fair Value Disclosure
Short-term investments	445,194	103,580
Long-term investments	7,531	397
Recurring \| Level 2 \| Money market funds
Assets, Fair Value Disclosure
Cash equivalents:	0	0
Recurring \| Level 2 \| Commercial paper
Assets, Fair Value Disclosure
Cash equivalents:	9,304	77,794
Recurring \| Level 2 \| Corporate notes and bonds
Assets, Fair Value Disclosure
Cash equivalents:	6,903	7,949
Recurring \| Level 2 \| Certificates of deposit
Assets, Fair Value Disclosure
Cash equivalents:	$ 3,044
Recurring \| Level 2 \| U.S. government and agency securities
Assets, Fair Value Disclosure
Cash equivalents:		$ 36,995

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 noncurrent.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
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-URI https://asc.fasb.org/extlink&oid=124258926&loc=SL82898722-210454

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
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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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