Cash Equivalents and Investments - Schedule of Debt Securities, Available-for-sale, Unrealized Loss Position, Fair Value (Details) - USD ($)	Jan. 31, 2025	Jan. 31, 2024
Cash Equivalents, Fair Value
Less than 12 months, fair value		$ 338,893,000
12 months or greater, fair value		0
Total, fair value		338,893,000
Cash Equivalents, Gross Unrealized Losses
Less than 12 months, accumulated losses		(2,000)
12 months or greater, accumulated losses		0
Total, accumulated losses		(2,000)
Investments, Fair Value
Less than 12 months, fair value		1,395,409,000
12 months or greater, fair value		513,815,000
Total, fair value		1,909,224,000
Investments, Gross Unrealized Losses
Less than 12 months, accumulated losses		(2,728,000)
12 months or greater, accumulated losses		(5,465,000)
Total, accumulated losses		(8,193,000)
Cash Equivalents And Debt Securities, Available-For-Sale [Abstract]
Less than 12 months, fair value		1,734,302,000
12 months or greater, fair value		513,815,000
Total, fair value		2,248,117,000
Cash Equivalents And Debt Securities, Available-For-Sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 months, accumulated losses		(2,730,000)
12 months or greater, accumulated losses		(5,465,000)
Total, accumulated losses	$ 0	(8,195,000)
Corporate notes and bonds
Investments, Fair Value
Less than 12 months, fair value		625,766,000
12 months or greater, fair value		321,952,000
Total, fair value		947,718,000
Investments, Gross Unrealized Losses
Less than 12 months, accumulated losses		(1,259,000)
12 months or greater, accumulated losses		(2,135,000)
Total, accumulated losses		(3,394,000)
U.S. government and agency securities
Investments, Fair Value
Less than 12 months, fair value		525,408,000
12 months or greater, fair value		191,863,000
Total, fair value		717,271,000
Investments, Gross Unrealized Losses
Less than 12 months, accumulated losses		(1,323,000)
12 months or greater, accumulated losses		(3,330,000)
Total, accumulated losses		(4,653,000)
Commercial paper
Investments, Fair Value
Less than 12 months, fair value		172,422,000
12 months or greater, fair value		0
Total, fair value		172,422,000
Investments, Gross Unrealized Losses
Less than 12 months, accumulated losses		(131,000)
12 months or greater, accumulated losses		0
Total, accumulated losses		(131,000)
Certificates of deposit
Investments, Fair Value
Less than 12 months, fair value		71,813,000
12 months or greater, fair value		0
Total, fair value		71,813,000
Investments, Gross Unrealized Losses
Less than 12 months, accumulated losses		(15,000)
12 months or greater, accumulated losses		0
Total, accumulated losses		(15,000)
U.S. government securities
Cash Equivalents, Fair Value
Less than 12 months, fair value		338,893,000
12 months or greater, fair value		0
Total, fair value		338,893,000
Cash Equivalents, Gross Unrealized Losses
Less than 12 months, accumulated losses		(2,000)
12 months or greater, accumulated losses		0
Total, accumulated losses		$ (2,000)