Note 12 - Stock Repurchase Program - Schedule of Stock Purchases (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended											18 Months Ended	63 Months Ended
	Jan. 31, 2023	Oct. 31, 2022	[1]	Jul. 31, 2022	[1]	Apr. 30, 2022	[1]	Jan. 31, 2022	[1]	Oct. 31, 2021	[1]	Jan. 31, 2023	Jul. 31, 2021	Apr. 30, 2021
Number of Shares Purchased (in shares)	85,307	150		1,639		180,503		0		6,290		3,377,522	3,103,633
Average Price Paid per Share (in dollars per share)	$ 0.68	$ 0.70		$ 0.84		$ 0.91		$ 0		$ 0.62		$ 0.42	$ 0.38
Number of Shares Purchased as Part of Publicly Announced Plans or Programs (in shares)	85,307	150		1,639		180,503		0		6,290		3,377,522	3,103,633
Approximate Dollar Value of Shares That May Yet Be Purchased Under the Plan or Programs	$ 2,595	$ 2,653		$ 2,653		$ 2,655		$ 2,819		$ 2,819		$ 2,595		$ 2,823

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