Note 10 - Per Share Data - Reconciliation of the Basic and Diluted Loss Per Share (Details) - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Net (loss)/income	$ (8,897,529)	$ 1,629,777
Less: Change in fair value of warrants		(3,136,265)
Net (loss)/income, adjusted for change in fair value of warrants for diluted earnings per share	$ (8,897,529)	$ (1,506,488)
Weighted average shares outstanding: basic (in shares)	81,240,105	80,913,320
Effect of potential common shares (in shares)		1,225,788
Weighted average shares outstanding: diluted (in shares)	81,240,105	82,139,108
Basic (loss) income per share (in dollars per share)	$ (0.11)	$ 0.02
Diluted (loss) per share (in dollars per share)	$ (0.11)	$ (0.02)