Note 13 - Restatement to Previously Issued Condensed Consolidated Financial Statements - Restatements (Details) - USD ($)	3 Months Ended			6 Months Ended	9 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Sep. 30, 2017	Jun. 30, 2018	Sep. 30, 2018	Sep. 30, 2017
Deemed dividend attributable to preferred stock		$ (11,479,308)		$ (11,479,308)	$ (11,479,308)	$ (2,568,132)
Net loss applicable to common stockholders	$ (3,309,866)	$ (15,621,885)	$ (2,184,510)	$ (17,496,267)	$ (20,806,133)	$ (8,697,685)
Loss per common share -basic and diluted (in dollars per share)	$ (0.64)	$ (5.08)	$ (2.11)	$ (6.11)	$ (5.71)	$ (13.23)
Issuance of Series B convertible preferred stock, net of issuance costs					$ 12,290,551
Deemed Dividend on Series B convertible preferred stock
Conversion of Series B convertible preferred stock to common stock
Additional Paid in Capital, Convertible Preferred Stock [Member]
Issuance of Series B convertible preferred stock, net of issuance costs		$ 6,926,778			6,926,778
Deemed Dividend on Series B convertible preferred stock		11,479,308			11,479,308
Conversion of Series B convertible preferred stock to common stock		(7,821,992)			(10,106,990)
Additional Paid in Capital, Common Stock [Member]
Issuance of Series B convertible preferred stock, net of issuance costs				$ 5,363,759	5,363,759
Deemed Dividend on Series B convertible preferred stock				(11,479,308)	(11,479,308)
Conversion of Series B convertible preferred stock to common stock				7,422,013	$ 9,590,167
Previously Reported [Member]
Deemed dividend attributable to preferred stock		(4,782,100)		(4,782,100)
Net loss applicable to common stockholders		$ (8,924,677)		$ (10,799,059)
Loss per common share -basic and diluted (in dollars per share)		$ (2.90)		$ (3.77)
Previously Reported [Member] | Additional Paid in Capital, Convertible Preferred Stock [Member]
Issuance of Series B convertible preferred stock, net of issuance costs		$ 12,290,537
Deemed Dividend on Series B convertible preferred stock		4,782,100
Conversion of Series B convertible preferred stock to common stock		$ (7,056,421)
Previously Reported [Member] | Additional Paid in Capital, Common Stock [Member]
Issuance of Series B convertible preferred stock, net of issuance costs				$ 0
Deemed Dividend on Series B convertible preferred stock				(4,782,100)
Conversion of Series B convertible preferred stock to common stock				$ 6,656,442