Short-Term Investments - Schedule of Short-Term Investments (Details) - USD ($) $ in Thousands	Apr. 30, 2026	Jan. 31, 2026
Debt Securities, Available-for-Sale [Line Items]
Amortized cost	$ 5,423,889	$ 5,110,621
Gross unrealized gains	10,590	30,496
Gross unrealized losses	(18,340)	(1,536)
Estimated fair value	5,416,139	5,139,581
Certificates of deposit
Debt Securities, Available-for-Sale [Line Items]
Amortized cost	27,710	27,710
Gross unrealized gains	0	0
Gross unrealized losses	(41)	(20)
Estimated fair value	27,669	27,690
Asset-backed securities
Debt Securities, Available-for-Sale [Line Items]
Amortized cost	204,923	260,136
Gross unrealized gains	1,091	1,912
Gross unrealized losses	(48)	(131)
Estimated fair value	205,966	261,917
Commercial paper
Debt Securities, Available-for-Sale [Line Items]
Amortized cost	44,755	75,367
Gross unrealized gains	1	8
Gross unrealized losses	(3)	0
Estimated fair value	44,753	75,375
Corporate notes and bonds
Debt Securities, Available-for-Sale [Line Items]
Amortized cost	3,293,436	3,133,825
Gross unrealized gains	7,838	21,684
Gross unrealized losses	(11,568)	(950)
Estimated fair value	3,289,706	3,154,559
Foreign government bonds
Debt Securities, Available-for-Sale [Line Items]
Amortized cost	219,830	232,271
Gross unrealized gains	511	1,206
Gross unrealized losses	(645)	(76)
Estimated fair value	219,696	233,401
Municipal securities
Debt Securities, Available-for-Sale [Line Items]
Amortized cost	41,453	37,231
Gross unrealized gains	75	222
Gross unrealized losses	(72)	0
Estimated fair value	41,456	37,453
U.S. agency obligations
Debt Securities, Available-for-Sale [Line Items]
Amortized cost	1,484	11,699
Gross unrealized gains	4	21
Gross unrealized losses	0	0
Estimated fair value	1,488	11,720
U.S. treasury securities
Debt Securities, Available-for-Sale [Line Items]
Amortized cost	1,590,298	1,332,382
Gross unrealized gains	1,070	5,443
Gross unrealized losses	(5,963)	(359)
Estimated fair value	$ 1,585,405	$ 1,337,466

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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