Note 5 - Stockholders' Equity - Stock Option Activity (Details) - Equity Incentive Plan2007 [Member] - $ / shares	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Minimum [Member]
Label Balances, exercise price per share (in dollars per share)	$ 0.22	$ 0.23
Granted, exercise price per share (in dollars per share)		0.30
Plan classification, exercise price per share (in dollars per share)		0.30
Balance, exercise price per share (in dollars per share)	0.22	0.23
Maximum [Member]
Label Balances, exercise price per share (in dollars per share)	1.89	1.89
Granted, exercise price per share (in dollars per share)		0.58
Plan classification, exercise price per share (in dollars per share)		0.60
Balance, exercise price per share (in dollars per share)	$ 1.89	$ 1.89
Balances, options outstanding (in shares)	10,241,086	8,601,086
Balances, shares available (in shares)	1,758,914	3,398,914
Balances, weighted average price per share (in dollars per share)	$ 0.44	$ 0.44
Granted, options outstanding (in shares)	40,000	1,040,000
Granted, shares available (in shares)	(40,000)	(1,040,000)
Granted, exercise price per share (in dollars per share)	$ 0.45
Granted, weighted average price per share (in dollars per share)	$ 0.45	$ 0.35
Plan classification, options outstanding (in shares)		600,000
Plan classification, shares available (in shares)		(600,000)
Plan classification, weighted average price per share (in dollars per share)		$ 0.33
Balance, options outstanding (in shares)	10,018,586	10,241,086
Balance, shares available (in shares)	1,981,414	2,158,914
Balances, weighted average price per share (in dollars per share)	$ 0.46	$ 0.43
Cancelled, options outstanding (in shares)	(262,500)
Cancelled, shares available (in shares)	262,500
Cancelled, exercise price per share (in dollars per share)	$ 0.40
Cancelled, weighted average price per share (in dollars per share)	$ 0.40