Cash Equivalents and Investments - Investments With Gross Unrealized Loss Positions (Details) $ in Thousands	Oct. 31, 2021 USD ($)
Cash Equivalents, Fair Value
Less than 12 months, fair value	$ 23,056
12 months or greater, fair value	0
Total, fair value	23,056
Cash Equivalents, Gross Unrealized Losses
Less than 12 months, accumulated losses	(1)
12 months or greater, accumulated losses	0
Total, accumulated losses	(1)
Investments, Fair Value
Less than 12 months, fair value	2,891,892
12 months or greater, fair value	0
Total, fair value	2,891,892
Investments, Gross Unrealized Losses
Less than 12 months, accumulated losses	(3,763)
12 months or greater, accumulated losses	0
Total, accumulated losses	(3,763)
Cash Equivalents And Debt Securities, Available-For-Sale [Abstract]
Less than 12 months, fair value	2,914,948
12 months or greater, fair value	0
Total, fair value	2,914,948
Cash Equivalents And Debt Securities, Available-For-Sale, Unrealized Loss Position, Accumulated Loss [Abstract]
Less than 12 months, accumulated losses	(3,764)
12 months or greater, accumulated losses	0
Total, accumulated losses	(3,764)
Commercial paper
Cash Equivalents, Fair Value
Less than 12 months, fair value	17,998
12 months or greater, fair value	0
Total, fair value	17,998
Cash Equivalents, Gross Unrealized Losses
Less than 12 months, accumulated losses	0
12 months or greater, accumulated losses	0
Total, accumulated losses	0
Investments, Fair Value
Less than 12 months, fair value	449,901
12 months or greater, fair value	0
Total, fair value	449,901
Investments, Gross Unrealized Losses
Less than 12 months, accumulated losses	(131)
12 months or greater, accumulated losses	0
Total, accumulated losses	(131)
Corporate notes and bonds
Cash Equivalents, Fair Value
Less than 12 months, fair value	5,058
12 months or greater, fair value	0
Total, fair value	5,058
Cash Equivalents, Gross Unrealized Losses
Less than 12 months, accumulated losses	(1)
12 months or greater, accumulated losses	0
Total, accumulated losses	(1)
Investments, Fair Value
Less than 12 months, fair value	2,170,442
12 months or greater, fair value	0
Total, fair value	2,170,442
Investments, Gross Unrealized Losses
Less than 12 months, accumulated losses	(3,278)
12 months or greater, accumulated losses	0
Total, accumulated losses	(3,278)
U.S. government and agency securities
Investments, Fair Value
Less than 12 months, fair value	230,705
12 months or greater, fair value	0
Total, fair value	230,705
Investments, Gross Unrealized Losses
Less than 12 months, accumulated losses	(321)
12 months or greater, accumulated losses	0
Total, accumulated losses	(321)
Certificates of deposit
Investments, Fair Value
Less than 12 months, fair value	40,844
12 months or greater, fair value	0
Total, fair value	40,844
Investments, Gross Unrealized Losses
Less than 12 months, accumulated losses	(33)
12 months or greater, accumulated losses	0
Total, accumulated losses	$ (33)