Note 9 - Leases - Lease Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Rent expense (prior to adoption of ASC 842)	$ 0	$ 0	$ 2,149
Operating lease costs	2,000	1,541	0
Short-term lease costs	541	302	0
Total lease costs	2,541	1,843	$ 2,149
Operating cash flows – cash paid for operating lease liabilities	1,425	1,320
Non-cash – Operating lease right-of-use assets obtained in exchange for new lease liabilities	$ 243	$ 782
Weighted-average remaining lease term (in years) (Year)	2 years 9 months 18 days	3 years 7 months 6 days
Weighted average discount rate	5.61%	5.61%