Cash Equivalents and Investments - Schedule of Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value (Details) - USD ($) $ in Thousands	Jan. 31, 2024	Jan. 31, 2023
Cash Equivalents, Fair Value
Less than 12 months, fair value	$ 338,893	$ 12,348
12 months or greater, fair value	0	0
Total, fair value	338,893	12,348
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	1,395,409	2,105,083
12 months or greater, fair value	513,815	969,202
Total, fair value	1,909,224	3,074,285
Investments, Gross Unrealized Losses
Less than 12 months, accumulated losses	(2,728)	(14,735)
12 months or greater, accumulated losses	(5,465)	(24,012)
Total, accumulated losses	(8,193)	(38,747)
Cash Equivalents And Debt Securities, Available-For-Sale [Abstract]
Less than 12 months, fair value	1,734,302	2,117,431
12 months or greater, fair value	513,815	969,202
Total, fair value	2,248,117	3,086,633
Cash Equivalents And Debt Securities, Available-For-Sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 months, accumulated losses	(2,730)	(14,737)
12 months or greater, accumulated losses	(5,465)	(24,012)
Total, accumulated losses	(8,195)	(38,749)
Corporate notes and bonds
Investments, Fair Value
Less than 12 months, fair value	625,766	899,655
12 months or greater, fair value	321,952	736,431
Total, fair value	947,718	1,636,086
Investments, Gross Unrealized Losses
Less than 12 months, accumulated losses	(1,259)	(8,521)
12 months or greater, accumulated losses	(2,135)	(14,949)
Total, accumulated losses	(3,394)	(23,470)
U.S. government and agency securities
Investments, Fair Value
Less than 12 months, fair value	525,408	387,207
12 months or greater, fair value	191,863	232,771
Total, fair value	717,271	619,978
Investments, Gross Unrealized Losses
Less than 12 months, accumulated losses	(1,323)	(3,157)
12 months or greater, accumulated losses	(3,330)	(9,063)
Total, accumulated losses	(4,653)	(12,220)
Commercial paper
Investments, Fair Value
Less than 12 months, fair value	172,422	561,793
12 months or greater, fair value	0	0
Total, fair value	172,422	561,793
Investments, Gross Unrealized Losses
Less than 12 months, accumulated losses	(131)	(1,947)
12 months or greater, accumulated losses	0	0
Total, accumulated losses	(131)	(1,947)
Certificates of deposit
Investments, Fair Value
Less than 12 months, fair value	71,813	256,428
12 months or greater, fair value	0	0
Total, fair value	71,813	256,428
Investments, Gross Unrealized Losses
Less than 12 months, accumulated losses	(15)	(1,110)
12 months or greater, accumulated losses	0	0
Total, accumulated losses	(15)	$ (1,110)
U.S. government securities
Cash Equivalents, Fair Value
Less than 12 months, fair value	338,893
12 months or greater, fair value	0
Total, fair value	338,893
Cash Equivalents, Gross Unrealized Losses
Less than 12 months, accumulated losses	(2)
12 months or greater, accumulated losses	0
Total, accumulated losses	$ (2)