Note 2 - Liquidity and Going Concern (Details Textual) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Net Income (Loss) Attributable to Parent, Total	$ (880,421)	$ (463,008)	$ (3,600,000)	$ (1,600,000)	$ 700,000