Note 5 - Warranty Provisions and Claims (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Balance at beginning of year	$ 285	$ 336	$ 241
Warranty provisions	288	297	442
Warranty claims	350	348	347
Balance at end of year	$ 223	$ 285	$ 336