Note 6 - Stockholders' Equity - Assumptions Used to Determine Fair Value of Stock Options Granted (Details) - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Volatility	70.00%
Terms (years) (Year)		4 years
Expected dividend rate	0.00%	0.00%
Minimum [Member]
Effective Exercise price (in dollars per share)	$ 0.32	$ 0.47
Effective market price (in dollars per share)	$ 0.32	$ 0.47
Volatility		61.00%
Risk-free interest	0.71%	0.89%
Terms (years) (Year)	3 years
Maximum [Member]
Effective Exercise price (in dollars per share)	$ 0.50	$ 1.43
Effective market price (in dollars per share)	$ 0.45	$ 1.43
Volatility		68.00%
Risk-free interest	0.88%	1.01%
Terms (years) (Year)	4 years