Note 6 - Warrants (Tables)

3 Months Ended

12 Months Ended

Mar. 31, 2017

Dec. 31, 2016

Schedule of Stockholders' Equity Note, Warrants or Rights [Table Text Block]

As of March 31, 2016	Number of
	Shares		Price Range
Balance, December 31, 2015		13,779,438	$0.125	–	1.00
Issued		728,571		0.45
Expired		—		—
Balance, March 31, 2016		14,508,009	$0.125	–	1.00

As of March 31, 2017	Number of
	Shares			Price Range
Balance, December 31, 2016		20,035,114		$0.125	–	1.00
Issued		219,298			0.70
Exercised		(510,000	)	0.25	–	0.30
Balance, March 31, 2017		19,744,412		$0.125	–	1.00

	Number of
	Shares			Price Range
Outstanding as of December 31, 2014		8,838,122		$0.125	-	1.00
Issued		12,693,395		0.30	-	0.45
Exercised		—		0.30	-	0.50
Expired		(7,752,079	)	0.25	-	0.75
Outstanding as of December 31, 2015		13,779,438		$0.125	-	1.00
Prior year extensions		4,634,637			0.30
Issued		6,822,855		0.35	-	0.75
Exercised		(2,818,271	)	0.25	-	0.40
Expired		(2,383,545	)	0.55	-	0.75
Outstanding as of December 31, 2016		20,035,114		$0.125	-	1.00

Schedule Of Assumptions Used To Determine Fair Value Of Warrants [Table Text Block]

	2016			2017
Risk free interest rate		1.36	%		1.93	%
Expected volatility		315	%		297	%
Expected dividend yield		—			—
Forfeiture rate		—			—
Expected life in years		5			5

	2015			2016
Risk free interest rate	.97	-	1.60%	.95	-	1.96%
Expected volatility	255	-	332%	301	-	315%
Expected dividend yield		-			-
Forfeiture rate		-			-
Expected life in years	3	-	5	3	-	5

- Definition

Tabular disclosure of warrants or rights issued. Warrants and rights outstanding are derivative securities that give the holder the right to purchase securities (usually equity) from the issuer at a specific price within a certain time frame. Warrants are often included in a new debt issue to entice investors by a higher return potential. The main difference between warrants and call options is that warrants are issued and guaranteed by the company, whereas options are exchange instruments and are not issued by the company. Also, the lifetime of a warrant is often measured in years, while the lifetime of a typical option is measured in months. Disclose the title of issue of securities called for by warrants and rights outstanding, the aggregate amount of securities called for by warrants and rights outstanding, the date from which the warrants or rights are exercisable, and the price at which the warrant or right is exercisable.

+ References + Details