Cash Equivalents and Investments - Schedule of Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value (Details) - USD ($) $ in Thousands	Apr. 30, 2024	Jan. 31, 2024
Cash Equivalents, Fair Value
Less than 12 months, fair value	$ 321,837	$ 338,893
12 months or greater, fair value	0	0
Total, fair value	321,837	338,893
Cash Equivalents, Gross Unrealized Losses
Less than 12 months, accumulated losses	(21)	(2)
12 months or greater, accumulated losses	0	0
Total, accumulated losses	(21)	(2)
Investments, Fair Value
Less than 12 months, fair value	2,135,028	1,395,409
12 months or greater, fair value	357,960	513,815
Total, fair value	2,492,988	1,909,224
Investments, Gross Unrealized Losses
Less than 12 months, accumulated losses	(9,789)	(2,728)
12 months or greater, accumulated losses	(3,937)	(5,465)
Total, accumulated losses	(13,726)	(8,193)
Cash Equivalents And Debt Securities, Available-For-Sale [Abstract]
Less than 12 months, fair value	2,456,865	1,734,302
12 months or greater, fair value	357,960	513,815
Total, fair value	2,814,825	2,248,117
Cash Equivalents And Debt Securities, Available-For-Sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 months, accumulated losses	(9,810)	(2,730)
12 months or greater, accumulated losses	(3,937)	(5,465)
Total, accumulated losses	(13,747)	(8,195)
Corporate notes and bonds
Investments, Fair Value
Less than 12 months, fair value	974,840	625,766
12 months or greater, fair value	206,956	321,952
Total, fair value	1,181,796	947,718
Investments, Gross Unrealized Losses
Less than 12 months, accumulated losses	(5,218)	(1,259)
12 months or greater, accumulated losses	(1,440)	(2,135)
Total, accumulated losses	(6,658)	(3,394)
U.S. government and agency securities
Investments, Fair Value
Less than 12 months, fair value	628,114	525,408
12 months or greater, fair value	151,004	191,863
Total, fair value	779,118	717,271
Investments, Gross Unrealized Losses
Less than 12 months, accumulated losses	(3,628)	(1,323)
12 months or greater, accumulated losses	(2,497)	(3,330)
Total, accumulated losses	(6,125)	(4,653)
Commercial paper
Investments, Fair Value
Less than 12 months, fair value	422,472	172,422
12 months or greater, fair value	0	0
Total, fair value	422,472	172,422
Investments, Gross Unrealized Losses
Less than 12 months, accumulated losses	(798)	(131)
12 months or greater, accumulated losses	0	0
Total, accumulated losses	(798)	(131)
Certificates of deposit
Investments, Fair Value
Less than 12 months, fair value	109,602	71,813
12 months or greater, fair value	0	0
Total, fair value	109,602	71,813
Investments, Gross Unrealized Losses
Less than 12 months, accumulated losses	(145)	(15)
12 months or greater, accumulated losses	0	0
Total, accumulated losses	(145)	(15)
U.S. government securities
Cash Equivalents, Fair Value
Less than 12 months, fair value	257,696	338,893
12 months or greater, fair value	0	0
Total, fair value	257,696	338,893
Cash Equivalents, Gross Unrealized Losses
Less than 12 months, accumulated losses	(1)	(2)
12 months or greater, accumulated losses	0	0
Total, accumulated losses	(1)	$ (2)
Commercial paper
Cash Equivalents, Fair Value
Less than 12 months, fair value	42,735
12 months or greater, fair value	0
Total, fair value	42,735
Cash Equivalents, Gross Unrealized Losses
Less than 12 months, accumulated losses	(7)
12 months or greater, accumulated losses	0
Total, accumulated losses	(7)
Corporate notes and bonds
Cash Equivalents, Fair Value
Less than 12 months, fair value	21,406
12 months or greater, fair value	0
Total, fair value	21,406
Cash Equivalents, Gross Unrealized Losses
Less than 12 months, accumulated losses	(13)
12 months or greater, accumulated losses	0
Total, accumulated losses	$ (13)