Note 12 - Subsequent Events (Details Textual)				1 Months Ended	3 Months Ended
	May 12, 2019 shares	Apr. 30, 2019	Apr. 26, 2019 USD ($) shares	Mar. 31, 2019 shares	Mar. 31, 2019 USD ($) shares	Mar. 31, 2018 USD ($)
Proceeds from Issuance of Convertible Preferred Stock | $					$ 240,000	$ 590,000
Conversion of Series F Preferred Stock Into Common Stock [Member]
Conversion of Stock, Shares Converted				180	180
Conversion of Stock, Shares Issued				40,000	40,000
Series G Convertible Preferred Stock [Member]
Conversion of Stock, Shares Converted					0
Subsequent Event [Member] | Reverse Stock Split [Member]
Stockholders' Equity Note, Stock Split, Conversion Ratio		500
Subsequent Event [Member] | Conversion of Series F Preferred Stock Into Common Stock [Member]
Conversion of Stock, Shares Converted	94
Conversion of Stock, Shares Issued	53,600
Subsequent Event [Member] | Series I Warrants [Member]
Class Of Warrant Or Right Issued During Period			33,334
Subsequent Event [Member] | Series G Convertible Preferred Stock [Member]
Proceeds from Issuance of Convertible Preferred Stock | $			$ 250,000
Stock Issued During Period, Shares, New Issues			250