Note 10 - Stock Option Activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Employees and Non-employee Directors [Member]
Granted to non-employee directors (in shares)	120,000
Granted to non-employee directors (in dollars per share)	$ 1.58
Options outstanding (in shares)	580,000	1,070,000
Options outstanding (in dollars per share)	$ 1.58	$ 1.58
Exercised (in shares)	(475,000)	(490,000)
Exercised (in dollars per share)	$ 1.61	$ 1.58
Canceled/expired/forfeited (in shares)
Canceled/expired/forfeited (in dollars per share)
Options outstanding (in shares)	225,000	580,000
Options outstanding (in dollars per share)	$ 1.52	$ 1.58
Granted to non-employee directors (in shares)	120,000	0
Options exercisable (in shares)	65,000
Options exercisable (in dollars per share)	$ 1.43