Note 11 - Warrants to Purchase Common Stock (Details)	6 Months Ended
	Jun. 30, 2016 $ / shares shares
Options Outstanding | shares	67,879
Options Granted | shares	1,000,000
Options Expired | shares
Options Outstanding | shares	1,067,879
Options exercisable at End | shares	354,911
Outstanding at Beginning, Weighted-Average Exercise Price | $ / shares	$ 21.40
Weighted- Average Exercise Price, Granted | $ / shares	1.75
Weighted- Average Exercise Price, Expired | $ / shares
Outstanding at Ending, Weighted-Average Exercise Price | $ / shares	3.00
Weighted- Average exercisable at End | $ / shares	$ 4.99
Weighted- Average Remaining Contractual Term, Beginning balance	7 years 2 months 1 day
Weighted- Average Remaining Contractual Term, Granted	5 years
Weighted- Average Remaining Contractual Term, Ending Balance	5 years 2 months 19 days
Weighted- Average Remaining Contractual Term, exercisable at End	4 years 11 months 12 days
Warrant [Member]
Options Outstanding | shares	78,462
Options Granted | shares	66,666
Options Expired | shares	(2,475)
Options Outstanding | shares	142,653
Options exercisable at End | shares	142,653
Outstanding at Beginning, Weighted-Average Exercise Price | $ / shares	$ 29.55
Weighted- Average Exercise Price, Granted | $ / shares	2.50
Weighted- Average Exercise Price, Expired | $ / shares	50.50
Outstanding at Ending, Weighted-Average Exercise Price | $ / shares	17.42
Weighted- Average exercisable at End | $ / shares	$ 17.42
Weighted- Average Remaining Contractual Term, Beginning balance	3 years 5 months 5 days
Weighted- Average Remaining Contractual Term, Granted	2 years
Weighted- Average Remaining Contractual Term, Ending Balance	2 years 6 months
Weighted- Average Remaining Contractual Term, exercisable at End	2 years 6 months