Note 10 - Shareholders' Equity - Stock Option Activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Options outstanding (in shares)	225,000	580,000
Options outstanding (in dollars per share)	$ 1.52	$ 1.58
Granted (in shares)	855,000	120,000
Exercised (in shares)	(15,000)	(475,000)
Exercised (in dollars per share)	$ 1.15	$ 1.61
Canceled/expired/forfeited (in shares)
Canceled/expired/forfeited (in dollars per share)
Options outstanding (in shares)	1,065,000	225,000
Options outstanding (in dollars per share)	$ 2.06	$ 1.52
Options exercisable (in shares)	130,000
Options exercisable (in dollars per share)	$ 1.53
Non-Employee Directors [Member]
Granted (in shares)	45,000	120,000
Granted (in dollars per share)	$ 3.45	$ 1.58
Employees [Member]
Granted (in shares)	810,000
Granted (in dollars per share)	$ 2.12