Investments - Cash Equivalents and Available-for-Sale Marketable Securities (Details) - USD ($) $ in Thousands	Apr. 30, 2022	Apr. 30, 2021	Apr. 30, 2020
Cash equivalents:
Amortized Cost	$ 339,528	$ 115,355	$ 33,104
Available-for-sale marketable securities:
Total cash equivalents and available-for-sale marketable securities, Amortized Cost	916,988	1,021,340
Total cash equivalents and available-for-sale marketable securities, Gross Unrealized Gain	20	101
Total cash equivalents and available-for-sale marketable securities, Gross Unrealized Loss	(2,168)	(20)
Total cash equivalents and available-for-sale marketable securities	914,840	1,021,421
Money market funds
Cash equivalents:
Amortized Cost	107,726	43,401
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	107,726	43,401
U.S. treasury securities
Available-for-sale marketable securities:
Amortized Cost	12,764	57,993
Gross Unrealized Gains	0	5
Gross Unrealized Losses	(1)	0
Estimated Fair Value	12,763	57,998
Commercial paper
Cash equivalents:
Amortized Cost	142,511	0
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	142,511	0
Available-for-sale marketable securities:
Amortized Cost	241,134	494,625
Gross Unrealized Gains	0	64
Gross Unrealized Losses	(2)	(13)
Estimated Fair Value	241,132	494,676
Corporate debt securities
Cash equivalents:
Amortized Cost	8,889	0
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(5)	0
Estimated Fair Value	8,884	0
Available-for-sale marketable securities:
Amortized Cost	289,646	2,369
Gross Unrealized Gains	20	0
Gross Unrealized Losses	(1,937)	(1)
Estimated Fair Value	287,729	2,368
Certificates of deposit
Cash equivalents:
Amortized Cost	3,000	0
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	3,000	0
Available-for-sale marketable securities:
Amortized Cost	97,205	422,952
Gross Unrealized Gains	0	32
Gross Unrealized Losses	0	(6)
Estimated Fair Value	97,205	422,978
U.S. government agencies securities
Available-for-sale marketable securities:
Amortized Cost	14,113	0
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(223)	0
Estimated Fair Value	$ 13,890	$ 0

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