Segment and Geographic Information - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Apr. 30, 2022	Apr. 30, 2021	Apr. 30, 2020
Disaggregation of Revenue [Line Items]
Total revenue	$ 106,477	$ 58,697	$ 53,835
United States
Disaggregation of Revenue [Line Items]
Total revenue	27,696	35,655	33,710
Mainland China
Disaggregation of Revenue [Line Items]
Total revenue	37,699	363	180
Mexico
Disaggregation of Revenue [Line Items]
Total revenue	10,140	8,118	2,149
Hong Kong
Disaggregation of Revenue [Line Items]
Total revenue	11,696	4,492	7,488
Rest of World
Disaggregation of Revenue [Line Items]
Total revenue	$ 19,246	$ 10,069	$ 10,308