Note 8 - Subsequent Events (Details Textual)	1 Months Ended
	Apr. 30, 2017 USD ($) $ / shares shares	Mar. 31, 2017 USD ($) $ / shares
Stock Purchase Warrants [Member]
Class of Warrant or Right, Exercised During Period, Exercise Price		$ 3.25
Proceeds from Warrant Exercises | $		$ 2,200,000
Subsequent Event [Member]
Class of Warrant or Right, Ratio of Warrants Exercised to Warrants Issued	3
Subsequent Event [Member] | Stock Purchase Warrants [Member]
Number of Warrants and Options Exercised | shares	153,847
Class of Warrant or Right, Exercised During Period, Exercise Price	$ 3.25
Proceeds from Warrant Exercises | $	$ 500,000
Subsequent Event [Member] | Inducement Warrants [Member]
Number of Warrants and Options Exercised | shares	51,283
Class of Warrant or Right, Exercised During Period, Exercise Price	$ 5.80