Stock-Based Compensation - Stock Option Activity (Details) $ / shares in Units, shares in Thousands, $ in Thousands	6 Months Ended	12 Months Ended
	Oct. 31, 2021 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	3,412
Options exercised (in shares) | shares	(2,735)
Options cancelled (in shares) | shares	(1,960)
Balance at end of period (in shares) | shares	37,204	38,487
Vested and exercisable at end of period (in shares) | shares	14,843
Vested and expected to vest at end of period (in shares) | shares	37,825
Weighted Average Exercise Price
Balance at beginning of period (in dollars per share) | $ / shares	$ 6.39
Options granted (in dollars per share) | $ / shares	55.82
Options exercised (in dollars per share) | $ / shares	4.22
Options cancelled (in dollars per share) | $ / shares	10.48
Balance at end of period (in dollars per share) | $ / shares	10.86	$ 6.39
Vested and exercisable at end of period (in dollars per share) | $ / shares	4.48
Vested and expected to vest at end of period (in dollars per share) | $ / shares	$ 10.86
Weighted Average Remaining Contractual Life (years)
Balance at beginning of period	7 years 7 months 6 days	7 years 11 months 23 days
Balance at end of period	7 years 7 months 6 days	7 years 11 months 23 days
Vested and exercisable at end of period	6 years 5 months 4 days
Vested and expected to vest at end of period	7 years 7 months 6 days
Aggregate Intrinsic Value
Balance at beginning of period | $	$ 1,274,594	$ 2,304,714
Balance at end of period | $	1,274,594	$ 2,304,714
Vested and exercisable at end of period | $	603,201
Vested and expected to vest at end of period | $	$ 1,295,871