Investments and Fair Value Measurements - Financial Assets and Liabilities (Details) - USD ($) $ in Thousands	Jul. 31, 2024	Jan. 31, 2024
Assets
Short-term investments	$ 0	$ 99,591
Recurring
Assets
Total assets	3,699,049	3,155,634
Recurring \| Level 1
Assets
Total assets	1,508,798	2,362,444
Recurring \| Level 2
Assets
Total assets	2,190,251	793,190
Recurring \| Level 3
Assets
Total assets	0	0
Recurring \| Money market funds
Assets
Cash equivalents	1,505,049	2,360,173
Recurring \| Money market funds \| Level 1
Assets
Cash equivalents	1,505,049	2,360,173
Recurring \| Money market funds \| Level 2
Assets
Cash equivalents	0	0
Recurring \| Money market funds \| Level 3
Assets
Cash equivalents	0	0
Recurring \| U.S. Treasury securities
Assets
Cash equivalents	2,190,251	693,599
Short-term investments	0	99,591
Recurring \| U.S. Treasury securities \| Level 1
Assets
Cash equivalents	0	0
Short-term investments	0	0
Recurring \| U.S. Treasury securities \| Level 2
Assets
Cash equivalents	2,190,251	693,599
Short-term investments	0	99,591
Recurring \| U.S. Treasury securities \| Level 3
Assets
Cash equivalents	0	0
Short-term investments	0	0
Recurring \| Deferred compensation investments
Assets
Other assets	3,749	2,271
Recurring \| Deferred compensation investments \| Level 1
Assets
Other assets	3,749	2,271
Recurring \| Deferred compensation investments \| Level 2
Assets
Other assets	0	0
Recurring \| Deferred compensation investments \| Level 3
Assets
Other assets	$ 0	$ 0