Cash Equivalents and Investments - Schedule of Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value (Details) - USD ($) $ in Thousands	Jul. 31, 2024	Jan. 31, 2024
Cash Equivalents, Fair Value
Less than 12 months, fair value	$ 181,845	$ 338,893
12 months or greater, fair value	0	0
Total, fair value	181,845	338,893
Cash Equivalents, Gross Unrealized Losses
Less than 12 months, accumulated losses	(2)	(2)
12 months or greater, accumulated losses	0	0
Total, accumulated losses	(2)	(2)
Investments, Fair Value
Less than 12 months, fair value	1,011,610	1,395,409
12 months or greater, fair value	609,540	513,815
Total, fair value	1,621,150	1,909,224
Investments, Gross Unrealized Losses
Less than 12 months, accumulated losses	(1,240)	(2,728)
12 months or greater, accumulated losses	(3,128)	(5,465)
Total, accumulated losses	(4,368)	(8,193)
Cash Equivalents And Debt Securities, Available-For-Sale [Abstract]
Less than 12 months, fair value	1,193,455	1,734,302
12 months or greater, fair value	609,540	513,815
Total, fair value	1,802,995	2,248,117
Cash Equivalents And Debt Securities, Available-For-Sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 months, accumulated losses	(1,242)	(2,730)
12 months or greater, accumulated losses	(3,128)	(5,465)
Total, accumulated losses	(4,370)	(8,195)
Corporate notes and bonds
Investments, Fair Value
Less than 12 months, fair value	527,359	625,766
12 months or greater, fair value	276,449	321,952
Total, fair value	803,808	947,718
Investments, Gross Unrealized Losses
Less than 12 months, accumulated losses	(807)	(1,259)
12 months or greater, accumulated losses	(875)	(2,135)
Total, accumulated losses	(1,682)	(3,394)
U.S. government and agency securities
Investments, Fair Value
Less than 12 months, fair value	122,169	525,408
12 months or greater, fair value	333,091	191,863
Total, fair value	455,260	717,271
Investments, Gross Unrealized Losses
Less than 12 months, accumulated losses	(174)	(1,323)
12 months or greater, accumulated losses	(2,253)	(3,330)
Total, accumulated losses	(2,427)	(4,653)
Commercial paper
Investments, Fair Value
Less than 12 months, fair value	316,822	172,422
12 months or greater, fair value	0	0
Total, fair value	316,822	172,422
Investments, Gross Unrealized Losses
Less than 12 months, accumulated losses	(226)	(131)
12 months or greater, accumulated losses	0	0
Total, accumulated losses	(226)	(131)
Certificates of deposit
Investments, Fair Value
Less than 12 months, fair value	45,260	71,813
12 months or greater, fair value	0	0
Total, fair value	45,260	71,813
Investments, Gross Unrealized Losses
Less than 12 months, accumulated losses	(33)	(15)
12 months or greater, accumulated losses	0	0
Total, accumulated losses	(33)	(15)
U.S. government securities
Cash Equivalents, Fair Value
Less than 12 months, fair value	179,497	338,893
12 months or greater, fair value	0	0
Total, fair value	179,497	338,893
Cash Equivalents, Gross Unrealized Losses
Less than 12 months, accumulated losses	(2)	(2)
12 months or greater, accumulated losses	0	0
Total, accumulated losses	(2)	$ (2)
Commercial paper
Cash Equivalents, Fair Value
Less than 12 months, fair value	2,348
12 months or greater, fair value	0
Total, fair value	2,348
Cash Equivalents, Gross Unrealized Losses
Less than 12 months, accumulated losses	0
12 months or greater, accumulated losses	0
Total, accumulated losses	$ 0