Investments - Summary of Marketable Securities (Details) - USD ($) $ in Thousands	Apr. 30, 2023	Jan. 31, 2023
Marketable Securities [Line Items]
Amortized Cost	$ 4,612,875	$ 4,392,058
Gross Unrealized Gains	1,410	599
Gross Unrealized Losses	(47,440)	(66,821)
Estimated Fair Value	4,566,845	4,325,836
Commercial paper
Marketable Securities [Line Items]
Amortized Cost	61,013	77,701
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	61,013	77,701
Agency bonds
Marketable Securities [Line Items]
Amortized Cost	1,189,447	823,027
Gross Unrealized Gains	323	63
Gross Unrealized Losses	(10,734)	(12,440)
Estimated Fair Value	1,179,036	810,650
Corporate and other debt securities
Marketable Securities [Line Items]
Amortized Cost	521,480	555,354
Gross Unrealized Gains	268	385
Gross Unrealized Losses	(3,982)	(4,845)
Estimated Fair Value	517,766	550,894
U.S. government agency securities
Marketable Securities [Line Items]
Amortized Cost	2,770,605	2,910,572
Gross Unrealized Gains	819	150
Gross Unrealized Losses	(32,671)	(49,507)
Estimated Fair Value	2,738,753	2,861,215
Treasury bills
Marketable Securities [Line Items]
Amortized Cost	70,330	25,404
Gross Unrealized Gains	0	1
Gross Unrealized Losses	(53)	(29)
Estimated Fair Value	$ 70,277	$ 25,376

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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