Note 8 - Income Taxes - Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Unrecognized tax benefits at the beginning of year	$ 525	$ 390	$ 82
Additions for tax positions of current year	73	83	95
Additions for tax positions of prior years	113	57	213
Reductions for settlements with taxing authorities.
Reductions for lapses of the applicable statutes of limitations		(5)
Unrecognized tax benefits at the end of the year	$ 711	$ 525	$ 390