Note 17 - Subsequent Events (Details Textual) - USD ($)				2 Months Ended	3 Months Ended																12 Months Ended				60 Months Ended	84 Months Ended
	Jul. 20, 2023	Jul. 15, 2023	May 09, 2023	Jul. 15, 2023	Apr. 30, 2023		Jan. 31, 2023		Oct. 31, 2022		Jul. 31, 2022	[1]	Apr. 30, 2022	[1]	Jan. 31, 2022	[1]	Oct. 31, 2021	[1]	Jul. 31, 2021	[1]	Apr. 30, 2023		Apr. 30, 2022		Apr. 30, 2021	Apr. 30, 2023		Dec. 31, 2016
Gain (Loss) on Disposition of Property Plant Equipment, Excluding Oil and Gas Property and Timber Property																					$ 410,000		$ 75,000
Treasury Stock, Shares, Acquired (in shares)					2,000		85,307		150		1,639		180,503		0		6,290		0						3,103,633	3,379,522
Shares Acquired, Average Cost Per Share (in dollars per share)					$ 0.68	[1]	$ 0.68	[1]	$ 0.70	[1]	$ 0.84		$ 0.91		$ 0		$ 0.62		$ 0						$ 0.38	$ 0.42
Stock Repurchase Program, Authorized Amount					$ 4,000,000																4,000,000					$ 4,000,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount					$ 2,594	[1]	$ 2,595	[1]	$ 2,653,000	[1]	$ 2,653,000		$ 2,655,000		$ 2,819,000		$ 2,819,000		$ 2,823,000		$ 2,594	[1]	$ 2,655,000	[1]	$ 2,823,000	$ 2,594	[1]	$ 4,000
Subsequent Event [Member]
Stock Repurchase Program, Authorized Amount	$ 9,000,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 2,600,000
Subsequent Event [Member] | Separation and Mutual Release Agreement [Member]
Shares Acquired, Average Cost Per Share (in dollars per share)	$ 0.739
Subsequent Event [Member] | Brother of Former CEO [Member]
Treasury Stock, Shares, Acquired (in shares)		974,120
Shares Acquired, Average Cost Per Share (in dollars per share)		$ 0.70
Subsequent Event [Member] | Brother of Former CEO [Member] | Separation and Mutual Release Agreement [Member]
Treasury Stock, Shares, Acquired (in shares)	3,956,267
Severance Costs	$ 2,700,000
Subsequent Event [Member] | Craig Stewart [Member] | Separation and Mutual Release Agreement [Member]
Treasury Stock, Shares, Acquired (in shares)	1,933,402
Severance Costs	$ 1,800,000
Subsequent Event [Member] | Director [Member]
Shares Granted, Shares, Share-based Payment Arrangement, Forfeited (in shares)			1,100,000
Subsequent Event [Member] | Aircraft [Member]
Gain (Loss) on Disposition of Property Plant Equipment, Excluding Oil and Gas Property and Timber Property				$ 440,000

[1] These shares of common stock were purchased through a private transaction