Note 5 - Warrants (Details Textual) - USD ($)		3 Months Ended		6 Months Ended
	May 24, 2017	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Mar. 31, 2017	Jan. 13, 2017	Dec. 31, 2016	Dec. 30, 2016	Dec. 27, 2016	Sep. 17, 2016	Jul. 08, 2016	Dec. 31, 2015
Share Price									$ 0.83	$ 0.86	$ 0.70
Amortization of Debt Discount (Premium)				$ 1,723,396	$ 668,257
Derivative Liability, Current		$ 570,595		570,595				$ 663,560
Fair Value Adjustment of Warrants		$ (56,352)		$ (321,872)
Stock Issued During Period, Shares, Exercise of Warrants				510,000	0
Proceeds from Warrant Exercises				$ 153,000
Class of Warrant or Right, Issued During Period				990,727	1,828,571
Class of Warrant or Right, Outstanding		20,515,841	15,424,464	20,515,841	15,424,464			20,035,114					13,779,438
Summer 2017 Unit Offering [Member]
Debt Instrument, Convertible, Conversion Price	$ 0.42
Warrants Issued Concurrently With One Year Convertible Note [Member]
Discount On Convertible Note Payable									$ 280,000			$ 160,000
Derivative Liability, Current		$ 570,595		$ 570,595
Fair Value Adjustment of Warrants		$ 56,352		321,872
Class of Warrant or Right, Interest Expense				$ 228,000
Class of Warrant or Right, Number of Securities Called by Warrants or Rights									400,000			400,000
Class of Warrant or Right, Exercise Price of Warrants or Rights	0.42								$ 0.75			$ 0.65
Warrants Issued Concurrently to the Summer 2017 Unit Offering [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights	$ 0.65
Class of Warrant or Right, Issued During Period	219,048
Class of Warrant or Right, Outstanding	619,048
Warrants Issued Concurrently to the Summer 2017 Unit Offering 2 [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights	$ 0.42
Class of Warrant or Right, Issued During Period	314,285
Class of Warrant or Right, Outstanding	714,285
The 2015 Unit Offering [Member]
Discount On Convertible Note Payable			$ 535,000		$ 535,000
Class of Warrant or Right, Number of Securities Called by Warrants or Rights			1,528,571		1,528,571
Class of Warrant or Right, Exercise Price of Warrants or Rights			$ 0.45		$ 0.45
Warrants Issued Concurrently with Line of Credit [Member]
Debt Instrument, Unamortized Discount			$ 237,405		$ 237,405
Class of Warrant or Right, Number of Securities Called by Warrants or Rights			300,000		300,000
Class of Warrant or Right, Exercise Price of Warrants or Rights			$ 0.35		$ 0.35
Warrants With Exercise Price $0.30 [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights		370,000		370,000
Class of Warrant or Right, Exercise Price of Warrants or Rights		$ 0.30		$ 0.30
Warrants With Exercise Price $0.25 [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights		140,000		140,000
Class of Warrant or Right, Exercise Price of Warrants or Rights		$ 0.25		$ 0.25
Warrants Issued Concurrently to the Summer 2017 Unit Offering [Member]
Discount On Convertible Note Payable		$ 125,000		$ 125,000
Class of Warrant or Right, Number of Securities Called by Warrants or Rights		238,096		238,096
Class of Warrant or Right, Exercise Price of Warrants or Rights		$ 0.65		$ 0.65
Warrants Issued Concurrently with Winter 2016 Unit Offering [Member]
Discount On Convertible Note Payable						$ 125,000
Class of Warrant or Right, Number of Securities Called by Warrants or Rights						219,298	512,281
Class of Warrant or Right, Exercise Price of Warrants or Rights						$ 0.70	$ 0.70