Note 9 - Income Taxes (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Unrecognized Tax Benefits, Ending Balance	$ 820	$ 848	$ 711	$ 525
Deferred Tax Assets, Valuation Allowance, Total	1,824	1,388
Deferred Tax Assets, Operating Loss Carryforwards, Total	1,348	1,289
Deferred Tax Assets, Capital Loss Carryforwards	521	277
Foreign Tax Authority [Member] | AUSTRALIA
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	400	$ 100
Deferred Tax Assets, Operating Loss Carryforwards, Total	1,500
Deferred Tax Assets, Capital Loss Carryforwards	1,700
Foreign Tax Authority [Member] | FRANCE
Deferred Tax Assets, Operating Loss Carryforwards, Total	2,500
Foreign Tax Authority [Member] | SPAIN
Deferred Tax Assets, Operating Loss Carryforwards, Total	900
Foreign Tax Authority [Member] | NORWAY
Deferred Tax Assets, Operating Loss Carryforwards, Total	100
State and Local Jurisdiction [Member]
Tax Credit Carryforward, Amount	$ 1,600