Note 2 - Summary of Significant Accounting Policies - Inventory Reserves (Details) - SEC Schedule, 12-09, Reserve, Inventory [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Inventory reserves	$ 1,499	$ 104	$ 110
Charge to costs and expenses	202	1,401	(16)
Other additions (deductions)	59	(6)	10
Inventory reserves	$ 1,760	$ 1,499	$ 104