Note 11 - Stockholders' Equity (Details Textual) - USD ($)				1 Months Ended		3 Months Ended
	Jun. 29, 2018	Jun. 21, 2017	Dec. 21, 2016	Jun. 30, 2017	Jun. 30, 2016	Mar. 31, 2019
Stock Issued During Period, Shares, Issued for Services						0
Cross River Partners, L.P. [Member]
Class of Warrant or Right, Issued During Period				1,612,902
Class of Warrant or Right, Grants in Period, Grant-date Fair Value				$ 0.19
Warrants Expiration Period				5 years
Class of Warrant or Right, Issued During Period, Exercise Price				$ 0.31
Class of Warrant or Right, Exercised During Period	1,612,902
Class of Warrant or Right, Exercised During Period, Exercise Price	$ 0.005
Proceeds from Warrant Exercises	$ 500,000
Aggregate Intrinsic Value Of Warrants Exercised	$ 1,400,000
Warrants Issued in June 2016 [Member]
Class of Warrant or Right, Issued During Period					30,000
Class of Warrant or Right, Grants in Period, Grant-date Fair Value					$ 0.36
Class of Warrants or Rights, Vesting Period					1 year
Class of Warrants or Rights, Vested During the Period		15,000	15,000
Class of Warrant or Right, Exercise Price of Warrants or Rights						$ 0.70