Right-of-Use Assets and Lease Liabilities (Details) - USD ($) $ in Millions	12 Months Ended
	Apr. 30, 2021	Apr. 30, 2020
Disclosure Text Block [Abstract]
Operating Leases, Rent Expense	$ 1.6	$ 1.6
Operating Lease, Payments	$ 2.0	$ 1.7
Operating Lease, Weighted Average Remaining Lease Term	7 years 146 days
Operating Lease, Weighted Average Discount Rate, Percent	6.19%