Note 6 - Summary of Stock Option Activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2015	Dec. 31, 2014
Options outstanding - beginning of period (in shares)	1,316,068	274,746	274,746
Options outstanding - beginning of period (in dollars per share)	$ 5.98	$ 1.99	$ 1.99
Options exercised (in shares)	(119,822)
Options exercised (in dollars per share)	$ 2.34
Options expired (in shares)	(921,500)
Options expired (in dollars per share)	$ 7.64
Options outstanding - end of period (in dollars per share)	$ 5.98	$ 1.99	$ 1.99
Options exercisable at end of period (in shares)	68,688	206,064	137,376
Options exercisable at end of period (in dollars per share)	$ 1.99	$ 1.99	$ 1.99