Note 7 - Taxes on Income - Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reductions due to lapse of statute of limitations	$ (100)	$ (100)	$ (100)
Excluding Interest and Penalties [Member]
Balance at the beginning of year	400	399
Additions based on tax positions related to the current year	56	59
Additions for tax positions of prior years	85
Reductions due to lapse of statute of limitations	(64)	(58)
Balance at the end of year	$ 477	$ 400	$ 399