Note 9 - Commitments and Contingencies - Lease Cost (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Current lease cost	$ 19	$ 288	$ 33	$ 579
Long-term lease cost	241	23	512	43
Total operating lease cost	260	311	545	622
Amortization of right-of-use assets	22	37	47	95
Interest on lease liabilities	1	5	3	12
Total lease cost	$ 23	$ 42	$ 50	$ 107
Weighted-average lease term (years), operating (Year)	3 years 8 months 23 days	4 years 5 months 15 days	3 years 8 months 23 days	4 years 5 months 15 days
Weighted-average discount rate, operating	6.09%	6.08%	6.09%	6.08%
Weighted-average lease term (years), financing (Year)	2 years 5 months 12 days	1 year 9 months 10 days	2 years 5 months 12 days	1 year 9 months 10 days
Weighted-average discount rate, financing	5.76%	6.10%	5.76%	6.10%