Fair Value Measurements - Schedule of Financial Assets and Liabilities (Details) - USD ($) $ in Thousands	6 Months Ended		12 Months Ended
	Jul. 31, 2024	Jul. 31, 2023	Jan. 31, 2024
Short-term investments:
Investment in non-marketable equity securities	$ 18,400		$ 12,900
Equity securities without readily determinable fair value, upward price adjustment, annual amount		$ 1,300
Non-marketable Securities
Short-term investments:
Payments to acquire investments	5,500	$ 2,100
Fair Value, Recurring
Short-term investments:
Total financial assets	1,764,351		1,724,904
Level 1 | Fair Value, Recurring
Short-term investments:
Total financial assets	1,764,351		1,724,904
Level 2 | Fair Value, Recurring
Short-term investments:
Total financial assets	0		0
Level 3 | Fair Value, Recurring
Short-term investments:
Total financial assets	0		0
U.S. government treasury securities
Short-term investments:
Unrealized losses on US treasury stock	321		2,231
U.S. government treasury securities | Fair Value, Recurring
Short-term investments:
Short-term investments:	973,933		1,212,448
U.S. government treasury securities | Level 1 | Fair Value, Recurring
Short-term investments:
Short-term investments:	973,933		1,212,448
U.S. government treasury securities | Level 2 | Fair Value, Recurring
Short-term investments:
Short-term investments:	0		0
U.S. government treasury securities | Level 3 | Fair Value, Recurring
Short-term investments:
Short-term investments:	0		0
Money market funds | Fair Value, Recurring
Cash and cash equivalents:
Cash and cash equivalents:	790,418		512,456
Money market funds | Level 1 | Fair Value, Recurring
Cash and cash equivalents:
Cash and cash equivalents:	790,418		512,456
Money market funds | Level 2 | Fair Value, Recurring
Cash and cash equivalents:
Cash and cash equivalents:	0		0
Money market funds | Level 3 | Fair Value, Recurring
Cash and cash equivalents:
Cash and cash equivalents:	$ 0		$ 0