Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2022	Apr. 30, 2021	Apr. 30, 2020
Cash flows from operating activities:
Net income (loss)	$ (22,176)	$ (27,511)	$ 1,329
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Depreciation and amortization	4,793	2,218	1,813
Share-based compensation	9,188	2,570	1,247
Warrant contra revenue	640	0	0
Write-downs for excess and obsolete inventory	1,444	1,673	153
Impairment of assets	4,887	0	0
Changes in operating assets and liabilities
Accounts receivable	(15,879)	682	(10,548)
Inventories	(21,677)	(6,502)	1,303
Prepaid and other current assets	2,808	(7,016)	491
Other non-current assets	(1,654)	(1,528)	164
Accounts payable	4,748	1,336	1,008
Accrued expenses, compensation and other liabilities	9,601	(7,006)	8,910
Deferred revenue, net of contract assets	(7,555)	(1,277)	(16,123)
Net cash used in operating activities	(30,832)	(42,361)	(10,253)
Cash flows from investing activities:
Purchases of property and equipment	(17,580)	(6,056)	(8,832)
Net cash used in investing activities	(17,580)	(6,056)	(8,832)
Cash flows from financing activities:
Proceeds from issuance of ordinary shares upon initial public offering, net of underwriter discounts and offering costs	194,205	0	0
Proceeds from employee stock options exercises	2,731	1,448	721
Proceeds from issuance of convertible preferred shares, net of issuance costs	7,245	99,348	60,485
Payments for repurchase of ordinary shares	0	(22,908)	0
Net cash provided by financing activities	204,181	77,888	61,206
Effect of exchange rate changes on cash	(204)	378	30
Net increase in cash and cash equivalents	155,565	29,849	42,151
Cash and cash equivalents at beginning of the year	103,757	73,908	31,757
Cash and cash equivalents at end of the year	259,322	103,757	73,908
Supplemental cash flow information:
Income taxes paid	(427)	(1,219)	(595)
Property and equipment received and accrued in accounts payable	168	19	217
Conversion of convertible preferred share into ordinary share upon initial public offering	$ 205,210	$ 0	$ 0