Note 14 - Subsequent Events (Details Textual) - Series E Preferred Stock [Member] - USD ($)			3 Months Ended
	Aug. 13, 2018	Mar. 26, 2018	Jun. 30, 2018
Stock Issued During Period, Shares, New Issues		43,800	8,800
Shares Issued, Price Per Share		$ 25	$ 25
Proceeds from Issuance of Convertible Preferred Stock		$ 1,095,000	$ 220,000
Subsequent Event [Member]
Stock Issued During Period, Shares, New Issues	1,400
Shares Issued, Price Per Share	$ 25
Proceeds from Issuance of Convertible Preferred Stock	$ 35,000