Note 10 - Warrant Liability - Outstanding Warrant Liability (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015
The 2011 Warrants [Member]
July 2011 Warrants (in shares)	138,621
Warrants and Rights Outstanding	$ 242
Long-term Warrants [Member]
July 2011 Warrants (in shares)	285,619
Warrants and Rights Outstanding	$ 506
Short-term Warrants [Member]
July 2011 Warrants (in shares)	370,934
Warrants and Rights Outstanding	$ 666
October 2015 Warrants [Member]
July 2011 Warrants (in shares)	442,802
Warrants and Rights Outstanding	$ 845
July 2011, Long-term, Short-term, and October 2015 Warrants [Member]
July 2011 Warrants (in shares)	1,237,976
Warrants and Rights Outstanding	$ 2,259
July 2011 Warrants (in shares)	3,495,000		1,458,000
Warrants and Rights Outstanding	$ 2,259	$ 1,835	$ 1,450