Note 11 - Financial Instruments - Estimated Fair Value of Outstanding Warrants (Details) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended		12 Months Ended
	Jun. 30, 2017		Dec. 31, 2016		Jun. 30, 2016
Term (Year)	5 years		5 years
Warrant exercise price (in dollars per share)	$ 0.35	[1]	$ 1.97	[2]
Warrant fair value liability	$ 1,397		$ 3,222
Warrants outstanding (in shares)	2,399,141		2,673,406		5,273,820
Warrant shares outstanding (in shares)	17,081,886		3,381,791

[1] Applying the Variable Exercise Price as applicable at June 30, 2017

[2] Applying the Variable Exercise Price as applicable at December 31, 2016