Note 9 - Stock Repurchase Program - Schedule of Stock Purchases (Details) - USD ($)	3 Months Ended											20 Months Ended
	Jul. 31, 2018	[1]	Apr. 30, 2018	[1]	Jan. 31, 2018	[1]	Oct. 31, 2017	Jul. 31, 2017	Apr. 30, 2017	Jan. 31, 2017	[1]	Jul. 31, 2018		Dec. 31, 2016
Approximate Dollar Value of Shares That May Yet Be Purchased Under the Plan or Programs	$ 525		$ 531,000		$ 576,000		$ 715,000	$ 718,000	$ 718,000	$ 740,000		$ 525	[1]	$ 750,000
Number of Shares Purchased (in shares)	25,277		178,526		536,058		8,607		80,426	49,920		878,814
Average Price Paid per Share (in dollars per share)	$ 0.26		$ 0.25		$ 0.26		$ 0.30		$ 0.27	$ 0.20		$ 0.26
Number of Shares Purchased as Part of Publicly Announced Plans or Programs (in shares)	25,277		178,526		536,058		8,607		80,426	49,920		878,814
Number of Shares Purchased (in shares)	25,277		178,526		536,058		8,607		80,426	49,920		878,814

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