CONDENSED CONSOLIDATED STATEMENTS OF REDEEMABLE CONVERTIBLE PREFERRED STOCK, REDEEMABLE CONVERTIBLE CLASS A-1 COMMON STOCK AND STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit	Redeemable Convertible Preferred Stock	Redeemable Convertible A-1 Common Stock
Beginning Balance, shares (in shares) at Apr. 30, 2020						37,129,000	6,667,000
Beginning Balance, Amount at Apr. 30, 2020						$ 375,207	$ 18,800
Increase (Decrease) in Temporary Equity [Roll Forward]
Repayment of shareholder loan						$ 24,546
Ending Balance, shares (in shares) at Oct. 31, 2020						37,129,000	6,667,000
Ending Balance, Amount at Oct. 31, 2020						$ 399,753	$ 18,800
Beginning Balance, shares (in shares) at Apr. 30, 2020		31,210,000
Beginning Balance, Amount at Apr. 30, 2020	$ (182,697)	$ 31	$ 110,485	$ 424	$ (293,637)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repayment of shareholder loan	1,457		1,457
Issuance of Class A common stock (in shares)		1,771,000
Issuance of Class A common stock	3,063	$ 2	3,061
Vesting of early exercised Class A common stock options	1,325		1,325
Stock-based compensation expense	7,681		7,681
Other comprehensive loss	(362)			(362)
Net loss	(14,794)				(14,794)
Ending Balance, shares (in shares) at Oct. 31, 2020		32,981,000
Ending Balance, Amount at Oct. 31, 2020	(184,327)	$ 33	124,009	62	(308,431)
Beginning Balance, shares (in shares) at Jul. 31, 2020						37,129,000	6,667,000
Beginning Balance, Amount at Jul. 31, 2020						$ 375,207	$ 18,800
Increase (Decrease) in Temporary Equity [Roll Forward]
Repayment of shareholder loan						$ 24,546
Ending Balance, shares (in shares) at Oct. 31, 2020						37,129,000	6,667,000
Ending Balance, Amount at Oct. 31, 2020						$ 399,753	$ 18,800
Beginning Balance, shares (in shares) at Jul. 31, 2020		31,342,000
Beginning Balance, Amount at Jul. 31, 2020	(179,681)	$ 31	113,518	257	(293,487)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repayment of shareholder loan	1,457		1,457
Issuance of Class A common stock (in shares)		1,639,000
Issuance of Class A common stock	2,728	$ 2	2,726
Vesting of early exercised Class A common stock options	1,107		1,107
Stock-based compensation expense	5,201		5,201
Other comprehensive loss	(195)			(195)
Net loss	(14,944)				(14,944)
Ending Balance, shares (in shares) at Oct. 31, 2020		32,981,000
Ending Balance, Amount at Oct. 31, 2020	(184,327)	$ 33	124,009	62	(308,431)
Beginning Balance, shares (in shares) at Apr. 30, 2021						0	0
Beginning Balance, Amount at Apr. 30, 2021						$ 0	$ 0
Ending Balance, shares (in shares) at Oct. 31, 2021						0	0
Ending Balance, Amount at Oct. 31, 2021						$ 0	$ 0
Beginning Balance, shares (in shares) at Apr. 30, 2021		102,167,000
Beginning Balance, Amount at Apr. 30, 2021	$ 1,061,175	$ 102	1,410,325	81	(349,333)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Class A common stock upon exercise of stock options, net of repurchases (in shares)	2,735,000	2,667,000
Issuance of Class A common stock upon exercise of stock options, net of repurchases	$ 11,494	$ 3	11,491
Vesting of early exercised Class A common stock options	1,908		1,908
Vesting of restricted stock units (in shares)		37,000
Stock-based compensation expense	46,452		46,452
Other comprehensive loss	(321)			(321)
Net loss	(94,198)				(94,198)
Ending Balance, shares (in shares) at Oct. 31, 2021		104,871,000
Ending Balance, Amount at Oct. 31, 2021	1,026,510	$ 105	1,470,176	(240)	(443,531)
Beginning Balance, shares (in shares) at Jul. 31, 2021						0	0
Beginning Balance, Amount at Jul. 31, 2021						$ 0	$ 0
Ending Balance, shares (in shares) at Oct. 31, 2021						0	0
Ending Balance, Amount at Oct. 31, 2021						$ 0	$ 0
Beginning Balance, shares (in shares) at Jul. 31, 2021		103,868,000
Beginning Balance, Amount at Jul. 31, 2021	1,043,795	$ 104	1,430,296	187	(386,792)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Class A common stock upon exercise of stock options, net of repurchases (in shares)		974,000
Issuance of Class A common stock upon exercise of stock options, net of repurchases	6,492	$ 1	6,491
Vesting of early exercised Class A common stock options	849		849
Vesting of restricted stock units (in shares)		29,000
Stock-based compensation expense	32,540		32,540
Other comprehensive loss	(427)			(427)
Net loss	(56,739)				(56,739)
Ending Balance, shares (in shares) at Oct. 31, 2021		104,871,000
Ending Balance, Amount at Oct. 31, 2021	$ 1,026,510	$ 105	$ 1,470,176	$ (240)	$ (443,531)