Note 6 - Stock-based Compensation (Details) - Summary of Stock Option Activity (USD $)	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2014	Dec. 31, 2013
Stock options - common:
Outstanding - beginning of period	1,316,068	274,746	274,746
Outstanding - beginning of period	$ 5.98	$ 1.99	$ 1.99
Options exercised	(30,000)
Options exercised	$ 3.36
Options expired	(921,500)
Options expired	$ 7.64
Options outstanding - end of period	364,568	274,746	274,746
Options outstanding - end of period	$ 1.99	$ 1.99	$ 1.99
Exercisable at end of period	158,510	137,376
Exercisable at end of period	$ 1.99	$ 1.99