Note 8 - Subsequent Events (Details Textual) - USD ($)		1 Months Ended	3 Months Ended
	May 08, 2020	May 08, 2020	Mar. 31, 2020	Mar. 31, 2019
Class of Warrant or Right, Exercised (in shares)			1,124,071
Proceeds from Warrant Exercises			$ 393,425
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)			$ 0.35
Subsequent Event [Member]
Class of Warrant or Right, Exercised (in shares)		6,385,496
Proceeds from Warrant Exercises		$ 2,500,000
Proceeds from Warrant Exercises, and Issuance of New Warrants	$ 2,400,000
Subsequent Event [Member] | Warrants Issued Prior to the Exchange on May 8, 2020 [Member]
Class of Warrant or Right, Exercised (in shares)	5,000,000
Subsequent Event [Member] | New Warrants Issued May 8, 2020 [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)	5,000,000	5,000,000
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)	$ 0.5263	$ 0.5263
Warrants and Rights Outstanding, Term (Year)	5 years 182 days	5 years 182 days
Subsequent Event [Member] | The May 2020 PA Warrants [Member] | H.C Wainwright & Co., LLC [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)	250,000	250,000
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)	$ 0.5938	$ 0.5938
Warrants and Rights Outstanding, Term (Year)	5 years 182 days	5 years 182 days