Summary of Significant Accounting Policies (Details Narrative) - USD ($)	3 Months Ended		9 Months Ended
	Jan. 31, 2023	Jan. 31, 2022	Jan. 31, 2023	Jan. 31, 2022	Apr. 30, 2022
Accounting Policies [Abstract]
Revenue recognized for which the contract liability was recorded in the prior year	$ 8,300,000	$ 6,900,000	$ 35,200,000	$ 31,700,000
Change in revenue due to change in estimate	3,000,000	1,200,000	3,000,000	12,400,000
Restricted cash	400,000		400,000		$ 400,000
Capitalized Interest Costs, Including Allowance for Funds Used During Construction	100,000		400,000	0
Depreciation and amortization	1,900,000	$ 1,000,000	5,300,000	3,100,000
Impairment of long-lived assets			0	$ 0
Cash equivalents	$ 50,800,000		$ 50,800,000		$ 116,300,000