Fair Value Measurements - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Oct. 31, 2023	Jan. 31, 2023
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	$ 1,222,649	$ 643,215
Gross Unrealized Gains	0	105
Gross Unrealized Losses	(2,366)	(4,501)
Estimated Fair Value	1,220,283	638,819
Cash	425,400	578,900
Level 2 \| Available-for-sale securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	525,182	510,206
Gross Unrealized Gains	0	105
Gross Unrealized Losses	(2,366)	(4,501)
Estimated Fair Value	522,816	505,810
Money market funds \| Level 1 \| Cash Equivalents
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	697,467	133,009
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	697,467	133,009
Commercial paper \| Level 2 \| Cash Equivalents
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	26,950	9,992
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(5)	(2)
Estimated Fair Value	26,945	9,990
Commercial paper \| Level 2 \| Available-for-sale securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	96,544	85,957
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(37)	(258)
Estimated Fair Value	96,507	85,699
U.S. governmental securities \| Level 2 \| Cash Equivalents
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	38,784
Gross Unrealized Gains	0
Gross Unrealized Losses	0
Estimated Fair Value	38,784
U.S. governmental securities \| Level 2 \| Available-for-sale securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	105,680	38,344
Gross Unrealized Gains	0	4
Gross Unrealized Losses	(250)	(405)
Estimated Fair Value	105,430	37,943
Corporate notes and bonds \| Level 2 \| Available-for-sale securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost	257,224	367,930
Gross Unrealized Gains	0	101
Gross Unrealized Losses	(2,074)	(3,771)
Estimated Fair Value	$ 255,150	364,260
Municipal notes and bonds \| Level 2 \| Available-for-sale securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized Cost		7,983
Gross Unrealized Gains		0
Gross Unrealized Losses		(65)
Estimated Fair Value		$ 7,918

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (b)
-Publisher FASB
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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount 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. Excludes cash and cash equivalents within disposal group and discontinued operation.

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Amortized cost excluding accrued interest, after allowance for credit loss, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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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).

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