Note 4 - Restructuring Activities (Details Textual) - USD ($) $ in Thousands		12 Months Ended
	Jan. 24, 2018	Dec. 31, 2018	Dec. 31, 2016	Dec. 31, 2017
The 2018 Restructuring Plan [Member]
Restructuring and Related Cost, Number of Positions Eliminated, Period Percent	13.00%
Restructuring Costs, Total		$ 1,276
Restructuring and Related Cost, Cost Incurred to Date		0
The 2016 Restructuring Plan [Member]
Restructuring Costs, Total			$ 596
Restructuring and Related Cost, Cost Incurred to Date		$ 0		$ 0