Note 10 - Leases - Cumulative Effect of Changes for Adoption of New ASU (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Right of Use Operating Lease Asset	$ 394	$ 362	$ 832
Other accrued liabilities	2,099	1,976	6,077	6,099
Operating Lease Liability - Current	149	182	522
Operating Lease Liability - Non Current	237	180	310
Accumulated deficit	$ (114,603)	$ (110,325)	(102,473)	$ (102,495)
Accounting Standards Update 2018-11 [Member]
Right of Use Operating Lease Asset			832
Other accrued liabilities			(22)
Operating Lease Liability - Current			522
Operating Lease Liability - Non Current			310
Accumulated deficit			$ 22