Note 13 - Stockholders' (Deficit) - Cumulative Arrearage of Undeclared Dividends (Details) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Preferred Stock, Dividend, Cumulative Arrearage	$ 2,081,980	$ 2,081,980
Preferred Stock, Dividend, Cumulative Arrearage Per Share (in dollars per share)
Series B Preferred Stock [Member]
Preferred Stock, Dividend, Cumulative Arrearage	$ 609,887	$ 609,887
Preferred Stock, Dividend, Cumulative Arrearage Per Share (in dollars per share)	$ 3.05	$ 3.05
Series C Preferred Stock [Member]
Preferred Stock, Dividend, Cumulative Arrearage	$ 1,472,093	$ 1,472,093
Preferred Stock, Dividend, Cumulative Arrearage Per Share (in dollars per share)	$ 4.37	$ 4.37