Cash Equivalents and Investments - Schedule of Amortized Costs, Unrealized Gains and Losses and Estimated Fair Value of Cash Equivalents and Short-term Investments (Details) - USD ($) $ in Thousands	Jul. 31, 2022	Jan. 31, 2022
Cash and Cash Equivalents [Line Items]
Amortized Cost	$ 2,369,404	$ 2,405,617
Unrealized Gain	85	10
Unrealized Loss	(30,521)	(11,747)
Estimated Fair Value	2,338,968	2,393,880
Cash Equivalents
Cash and Cash Equivalents [Line Items]
Amortized Cost	78,012	152,223
Unrealized Gain	0	0
Unrealized Loss	0	0
Estimated Fair Value	78,012	152,223
Cash Equivalents | Money market funds
Cash and Cash Equivalents [Line Items]
Amortized Cost	78,012	152,223
Unrealized Gain	0	0
Unrealized Loss	0	0
Estimated Fair Value	78,012	152,223
Short-term Investments
Cash and Cash Equivalents [Line Items]
Amortized Cost	2,291,392	2,253,394
Unrealized Gain	85	10
Unrealized Loss	(30,521)	(11,747)
Estimated Fair Value	2,260,956	2,241,657
Short-term Investments | U.S. treasury securities
Cash and Cash Equivalents [Line Items]
Amortized Cost	2,022,707	1,922,344
Unrealized Gain	85	10
Unrealized Loss	(26,952)	(10,166)
Estimated Fair Value	1,995,840	1,912,188
Short-term Investments | Corporate debt securities
Cash and Cash Equivalents [Line Items]
Amortized Cost	268,685	331,050
Unrealized Gain	0	0
Unrealized Loss	(3,569)	(1,581)
Estimated Fair Value	$ 265,116	$ 329,469