Note 11 - Net Loss Per Ordinary Share - Basic and Diluted Net Loss Per Share (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net loss per ordinary share	$ (22,349)	$ (24,478)	$ (22,174)
Weighted-average ordinary shares outstanding-basic (in shares)	22,353,713	21,781,933	17,310,148
Dilutive effect of ordinary share equivalents resulting from ordinary share options, ordinary share warrants and preferred ordinary shares (as converted) (in shares)
Weighted-average ordinary shares outstanding-diluted (in shares)	22,353,713	21,781,933	17,310,148