Note 2 - Adoption of New Accounting Standard - Cumulative Effect of Adjustments for New Accounting Pronouncements on Consolidated Condensed Balance Sheet (Details) - USD ($) $ in Thousands		Mar. 31, 2019		Jan. 01, 2019		Dec. 31, 2018
Other noncurrent assets		$ 3,109	[1]	$ 3,281	[1]	$ 2,146
Accrued and other current liabilities		31,649		28,706		28,166
Noncurrent operating lease liabilities		452		595
Previous Accounting Guidance [Member]
Other noncurrent assets	[1]	2,120				2,146
Accrued and other current liabilities		31,112				28,166
Noncurrent operating lease liabilities
Adjustments for New Accounting Pronouncement [Member]
Other noncurrent assets	[1]	989		1,135
Accrued and other current liabilities		537		540
Noncurrent operating lease liabilities		$ 452		$ 595

[1] Operating lease assets balance at January 1, 2019.