Note 3 - Basis of Presentation and Summary of Significant Accounting Policies - Basic and Diluted Earnings Per Share (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Basic net loss per common share calculation:
Net loss	$ (18,369,810)	$ (1,364,518)
Accretion of Series A cumulative preferred dividends	(85,993)	(1,252,394)
Deemed dividend related to the make-whole provision for the conversion of Series A convertible preferred stock into common stock	(8,167,895)
Net loss attributable to common stockholders	$ (26,623,698)	$ (2,616,912)
Weighted average shares outstanding, basic (in shares)	3,242,301	827,575
Net loss per share of common stock, basic (in dollars per share)	$ (8.21)	$ (3.16)
Diluted net loss per common share calculation:
Net loss attributable to common stockholders	$ (26,623,698)	$ (2,616,912)
Change in fair value of warrant liability		(22,072,322)
Diluted net loss	$ (26,623,698)	$ (24,689,234)
Weighted average shares outstanding, basic (in shares)	3,242,301	827,575
Common stock equivalents arising from warrants (in shares)		20,515
Common stock equivalents (in shares)	3,242,301	848,090
Net loss per share of common stock, diluted (in dollars per share)	$ (8.21)	$ (29.11)