Note 5 - Income Taxes - Operating Loss Carryforwards (Details) $ in Thousands	Dec. 31, 2018 USD ($)
Net Operating Losses	$ 35,147
Year 1 [Member]
Net Operating Losses	259
Year 2 [Member]
Net Operating Losses	2,849
Year 3 [Member]
Net Operating Losses	4,168
Year 4 [Member]
Net Operating Losses	1,217
Year 5 [Member]
Net Operating Losses	646
Year 6 [Member]
Net Operating Losses	589
Year 7 [Member]
Net Operating Losses	873
Year 8 [Member]
Net Operating Losses	2,607
Year 9 [Member]
Net Operating Losses	2,512
Year 10 [Member]
Net Operating Losses	2,196
Year 11 [Member]
Net Operating Losses	1,232
Year 12 [Member]
Net Operating Losses	1,028
Year 13 [Member]
Net Operating Losses	437
Year 14 [Member]
Net Operating Losses	37
Year 15 [Member]
Net Operating Losses	6,409
Year 16 [Member]
Net Operating Losses	3,093
Year 17 [Member]
Net Operating Losses	$ 4,995