Note 7 - Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Lessee, Lease, Description [Line Items]
Operating Lease, Expense	$ 200	$ 100	$ 400
Operating Lease, Right-of-Use Asset	$ 200
Operating Lease, Liability, Statement of Financial Position [Extensible List]	us-gaap:LiabilitiesOtherThanLongtermDebtNoncurrent
Maximum
Lessee, Lease, Description [Line Items]
Remaining lease term	3 years