Stock-Based Compensation - Stock Option Activity (Details) $ / shares in Units, shares in Thousands, $ in Thousands	9 Months Ended	12 Months Ended
	Jan. 31, 2022 USD ($) $ / shares shares	Apr. 30, 2021 USD ($) $ / shares shares
Number of Stock Options Outstanding
Balance at beginning of period (in shares) | shares	38,487
Options granted (in shares) | shares	6,127
Options exercised (in shares) | shares	(4,174)
Options cancelled (in shares) | shares	(3,290)
Balance at end of period (in shares) | shares	37,150	38,487
Vested and exercisable at end of period (in shares) | shares	15,195
Vested and expected to vest at end of period (in shares) | shares	37,629
Weighted Average Exercise Price
Balance at beginning of period (in dollars per share) | $ / shares	$ 6.39
Options granted (in dollars per share) | $ / shares	46.23
Options exercised (in dollars per share) | $ / shares	4.76
Options cancelled (in dollars per share) | $ / shares	13.71
Balance at end of period (in dollars per share) | $ / shares	12.47	$ 6.39
Vested and exercisable at end of period (in dollars per share) | $ / shares	5.10
Vested and expected to vest at end of period (in dollars per share) | $ / shares	$ 12.47
Weighted Average Remaining Contractual Life (years)
Balance at beginning of period	7 years 7 months 2 days	7 years 11 months 23 days
Balance at end of period	7 years 7 months 2 days	7 years 11 months 23 days
Vested and exercisable at end of period	6 years 6 months
Vested and expected to vest at end of period	7 years 7 months 2 days
Aggregate Intrinsic Value
Balance at beginning of period | $	$ 515,266	$ 2,304,714
Balance at end of period | $	515,266	$ 2,304,714
Vested and exercisable at end of period | $	322,749
Vested and expected to vest at end of period | $	$ 521,914