Condensed Consolidated Statements of Convertible Preferred Shares and Shareholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Ordinary Shares	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Beginning balance (in shares) at Apr. 30, 2020	32,245,000
Beginning balance at Apr. 30, 2020	$ 98,617
Increase (Decrease) in Temporary Equity [Roll Forward]
Issuance of Series D+ convertible preferred shares, net of issuance costs (in shares)	9,934,000
Issuance of Series D+ convertible preferred shares, net of issuance costs	$ 49,481
Ending balance (in shares) at Jul. 31, 2020	42,179,000
Ending balance at Jul. 31, 2020	$ 148,098
Beginning balance (in shares) at Apr. 30, 2020		72,545,000
Beginning balance at Apr. 30, 2020	(9,408)	$ 4	$ 9,506	$ (151)	$ (18,767)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Ordinary shares issued under employee share plan (in shares)		352,000
Ordinary shares issued under employee share plan	237		237
Share-based compensation	391		391
Total comprehensive loss	(4,766)			74	(4,840)
Ending balance (in shares) at Jul. 31, 2020		72,898,000
Ending balance at Jul. 31, 2020	$ (13,546)	$ 4	10,134	(77)	(23,607)
Beginning balance (in shares) at Apr. 30, 2020	32,245,000
Beginning balance at Apr. 30, 2020	$ 98,617
Ending balance (in shares) at Jan. 31, 2021	50,809,000
Ending balance at Jan. 31, 2021	$ 198,053
Beginning balance (in shares) at Apr. 30, 2020		72,545,000
Beginning balance at Apr. 30, 2020	(9,408)	$ 4	9,506	(151)	(18,767)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive loss	(24,012)
Ending balance (in shares) at Jan. 31, 2021		67,864,000
Ending balance at Jan. 31, 2021	$ (53,528)	$ 3	11,372	262	(65,165)
Beginning balance (in shares) at Jul. 31, 2020	42,179,000
Beginning balance at Jul. 31, 2020	$ 148,098
Ending balance (in shares) at Oct. 31, 2020	42,179,000
Ending balance at Oct. 31, 2020	$ 148,098
Beginning balance (in shares) at Jul. 31, 2020		72,898,000
Beginning balance at Jul. 31, 2020	(13,546)	$ 4	10,134	(77)	(23,607)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Ordinary shares issued under employee share plan (in shares)		1,164,000
Ordinary shares issued under employee share plan	558		558
Share purchase (in shares)		(6,876,000)
Share repurchase	(22,908)	$ (1)	(934)		(21,973)
Share-based compensation	414		414
Total comprehensive loss	(14,272)			196	(14,468)
Ending balance (in shares) at Oct. 31, 2020		67,186,000
Ending balance at Oct. 31, 2020	$ (49,754)	$ 3	10,172	119	(60,048)
Increase (Decrease) in Temporary Equity [Roll Forward]
Issuance of Series D+ convertible preferred shares, net of issuance costs (in shares)	8,630,000
Issuance of Series D+ convertible preferred shares, net of issuance costs	$ 49,955
Ending balance (in shares) at Jan. 31, 2021	50,809,000
Ending balance at Jan. 31, 2021	$ 198,053
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Ordinary shares issued under employee share plan (in shares)		678,000
Ordinary shares issued under employee share plan	353		353
Share-based compensation	847		847
Total comprehensive loss	(4,974)			143	(5,117)
Ending balance (in shares) at Jan. 31, 2021		67,864,000
Ending balance at Jan. 31, 2021	$ (53,528)	$ 3	11,372	262	(65,165)
Beginning balance (in shares) at Apr. 30, 2021	50,809,000
Beginning balance at Apr. 30, 2021	$ 197,965
Increase (Decrease) in Temporary Equity [Roll Forward]
Issuance of Series D+ convertible preferred shares, net of issuance costs (in shares)	1,251,000
Issuance of Series D+ convertible preferred shares, net of issuance costs	$ 7,245
Ending balance (in shares) at Jul. 31, 2021	52,060,000
Ending balance at Jul. 31, 2021	$ 205,210
Beginning balance (in shares) at Apr. 30, 2021	68,282,000	68,282,000
Beginning balance at Apr. 30, 2021	$ (55,431)	$ 3	12,592	227	(68,253)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Ordinary shares issued under employee share plan (in shares)		554,000
Ordinary shares issued under employee share plan	461		461
Share-based compensation	1,075		1,075
Total comprehensive loss	(12,582)			(5)	(12,577)
Ending balance (in shares) at Jul. 31, 2021		68,836,000
Ending balance at Jul. 31, 2021	$ (66,477)	$ 3	14,128	222	(80,830)
Beginning balance (in shares) at Apr. 30, 2021	50,809,000
Beginning balance at Apr. 30, 2021	$ 197,965
Ending balance (in shares) at Jan. 31, 2022	0
Ending balance at Jan. 31, 2022	$ 0
Beginning balance (in shares) at Apr. 30, 2021	68,282,000	68,282,000
Beginning balance at Apr. 30, 2021	$ (55,431)	$ 3	12,592	227	(68,253)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive loss	$ (17,026)
Ending balance (in shares) at Jan. 31, 2022	141,020,000	141,020,000
Ending balance at Jan. 31, 2022	$ 305,689	$ 7	390,734	22	(85,074)
Beginning balance (in shares) at Jul. 31, 2021	52,060,000
Beginning balance at Jul. 31, 2021	$ 205,210
Ending balance (in shares) at Oct. 31, 2021	52,060,000
Ending balance at Oct. 31, 2021	$ 205,210
Beginning balance (in shares) at Jul. 31, 2021		68,836,000
Beginning balance at Jul. 31, 2021	(66,477)	$ 3	14,128	222	(80,830)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Ordinary shares issued under employee share plan (in shares)		667,000
Ordinary shares issued under employee share plan	587		587
Share-based compensation	1,307		1,307
Total comprehensive loss	(4,068)			32	(4,100)
Ending balance (in shares) at Oct. 31, 2021		69,503,000
Ending balance at Oct. 31, 2021	$ (68,651)	$ 3	16,022	254	(84,930)
Increase (Decrease) in Temporary Equity [Roll Forward]
Conversion of preferred shares into ordinary shares (in shares)	(52,060,000)
Conversion of preferred shares into ordinary shares	$ (205,210)
Ending balance (in shares) at Jan. 31, 2022	0
Ending balance at Jan. 31, 2022	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Ordinary shares issued under employee share plan (in shares)		1,073,000
Ordinary shares issued under employee share plan	1,067		1,067
Share-based compensation	1,438		1,438
Total comprehensive loss	(376)			(232)	(144)
Conversion of convertible preferred shares to ordinary shares (in shares)		52,060,000
Conversion of preferred shares into ordinary shares	205,210	$ 3	205,207
Issuance of common stock in connection with initial public offering, net of offering costs, underwriting discounts and commissions (in shares)		18,384,000
Issuance of common stock in connection with initial public offering, net of offering costs, underwriting discounts and commissions	166,594	$ 1	166,593
Warrant contra revenue	$ 407		407
Ending balance (in shares) at Jan. 31, 2022	141,020,000	141,020,000
Ending balance at Jan. 31, 2022	$ 305,689	$ 7	390,734	22	(85,074)
Beginning balance (in shares) at Jan. 30, 2022	52,059,826
Ending balance (in shares) at Jan. 31, 2022	0
Ending balance at Jan. 31, 2022	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Conversion of convertible preferred shares to ordinary shares (in shares)	52,059,826
Ending balance (in shares) at Jan. 31, 2022	141,020,000	141,020,000
Ending balance at Jan. 31, 2022	$ 305,689	$ 7	$ 390,734	$ 22	$ (85,074)