Note 13 - Loss Per Common Share - Calculation of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Net loss	$ (4,765)	$ (1,568)	$ (8,027)	$ (5,422)
Basic and diluted weighted average number of shares outstanding (in shares)	28,506,154	20,967,957	28,497,146	20,958,656
Basic and diluted loss per common share (in dollars per share)	$ (0.17)	$ (0.07)	$ (0.28)	$ (0.26)