Note 9 - Line of Credit (Details) - Line of Credit [Member] - USD ($)	1 Months Ended	9 Months Ended
	Mar. 31, 2017	Dec. 31, 2017
Note 9 - Line of Credit (Details) [Line Items]
Line of Credit Facility, Expiration Date	Mar. 31, 2018
Line of Credit Facility, Maximum Borrowing Capacity	$ 1,000,000
Line of Credit Facility, Interest Rate at Period End		5.319%
Proceeds from Lines of Credit		$ 800,000
Long-term Line of Credit	$ 200,000	1,000,000
Line of Credit Facility, Remaining Borrowing Capacity		$ 0
London Interbank Offered Rate (LIBOR) [Member]
Note 9 - Line of Credit (Details) [Line Items]
Debt Instrument, Basis Spread on Variable Rate	3.75%