Note 8 - Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Lessee, Lease, Description [Line Items]
Operating Lease, Expense	$ 200	$ 200	$ 100
Operating Lease, Right-of-Use Asset	100	200
Operating Lease, Liability	$ 110	$ 200
Operating Lease, Liability, Statement of Financial Position [Extensible List]	Other long-term liabilities	Other long-term liabilities
Other long-term liabilities.
Lessee, Lease, Description [Line Items]
Operating Lease, Liability	$ 31	$ 100
Maximum
Lessee, Lease, Description [Line Items]
Remaining lease term	2 years