Note 9 - Loss Per Share - Shares Used in Basic and Diluted Loss Per Common Share Computations (Details) - USD ($)		3 Months Ended		6 Months Ended
		Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Net loss attributable to common shareholders per common share: basic and diluted calculation		$ (3,577,378)	$ 1,444,706	$ (8,106,695)	$ (1,848,478)
Weighted average shared used in computation - basic (in shares)	[1]	9,838,152	2,960,937	7,362,240	2,274,754
Effect of diluted stock options, warrants and preferred stock (in shares)	[2]		3,046,141
Weighted average shared used in computation - diluted (in shares)		9,838,152	6,007,078	7,362,240	2,274,754
Gain (loss) per common share basic (in dollars per share)		$ (0.36)	$ 0.49	$ (1.10)	$ (0.81)
Gain (loss) per common share diluted (in dollars per share)		$ (0.36)	$ 0.24	$ (1.10)	$ (0.81)

[1] Includes 1,390,166 contingently issuable shares related to prefunded warrants when outstanding during the six months ended June 30, 2020 and 122,000 abeyance shares during the six months ended June 30, 2020.

[2] (2) 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: Six months ended June 30, 2020 2019 Options 818,117 729,975 Warrants 7,257,883 2,025,971 Convertible debt 574,367 130,307 Preferred stock: series B 79,246 79,246 Preferred stock: series D - 350,004 Preferred stock: series E - 1,484,634