Note 10 - Activity Related to Warrants (Details) - Warrant [Member] - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Balance outstanding (in shares)		699,281	882,627
Balance outstanding (in dollars per share)	$ 2.145	$ 1.30
Issued (in shares)		699,281
Issued (in dollars per share)		$ 2.145
Expired (in shares)		(882,627)
Expired (in dollars per share)		$ 1.30