Note 8 - Commitments and Contingencies - Leases Cost and Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating lease cost	$ 150
Total lease cost	150
Cash paid for amounts included in the measurement of lease liabilities for the first quarter 2019	176
Amortization of operating lease right-of-use assets	$ 104
Weighted average remaining lease term – operating leases (in years) (Year)	3 years 219 days
Average discount rate – operating leases	8.34%