Note 7 - Loss Per Share - Shares Used in Basic and Diluted Loss Per Common Share Computations (Details) - USD ($)		3 Months Ended		9 Months Ended
		Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Net loss attributable to common shareholders per common share: basic and diluted calculation		$ (4,134,313)	$ (2,506,869)	$ (5,982,791)	$ (6,640,301)
Weighted average common shares outstanding-basic (in shares)		3,146,609	1,325,261	2,581,014	1,217,829
Effect of diluted stock options, warrants and preferred stock (1) (in shares)	[1]
Weighted average common shares outstanding-diluted (in shares)		3,146,609	1,325,261	2,581,014	1,217,829
Loss per common share - basic and diluted (in dollars per share)		$ (1.31)	$ (1.89)	$ (2.32)	$ (5.45)

[1] The following is a summary of the number of underlying shares outstanding at the end of the respective periods that have been excluded from the diluted calculations because the effect on loss per common share would have been anti-dilutive: Three and Nine Months Ended September 30 2019 2018 Options 713,564 344,889 Warrants 2,108,277 331,927 Convertible debt 103,734 504,770 Preferred stock: series B 7,925 7,925 Preferred stock: series D 350,000 - Preferred stock: series E 461,503 -