Concentration of Risk (Details) - Customer Concentration Risk	3 Months Ended		9 Months Ended
	Jan. 31, 2022	Jan. 31, 2021	Jan. 31, 2022	Jan. 31, 2021
Customer receivables | Customer A
Concentration Risk [Line Items]
Concentration risk (as a percent)			31.30%	32.90%
Customer receivables | Customer B
Concentration Risk [Line Items]
Concentration risk (as a percent)			18.80%	21.10%
Sales revenue, gross | Customer A
Concentration Risk [Line Items]
Concentration risk (as a percent)	32.10%	31.80%	31.90%	30.10%
Sales revenue, gross | Customer B
Concentration Risk [Line Items]
Concentration risk (as a percent)	16.90%	18.40%	16.00%	18.20%