Note 7 - Taxes on Income - Unrecognized Tax Benefits (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reductions due to lapse of statute of limitations	$ (28,000)	$ (44,000)	$ (38,000)
Excluding Interest and Penalties [Member]
Balance at January 1,	399,000	462,000
Additions based on tax positions related to the current year	55,000	58,000
Additions for tax positions of prior years	4,000	2,000
Reductions due to lapse of statute of limitations	(59,000)	(123,000)
Balance at December 31,	$ 399,000	$ 399,000	$ 462,000