Note 4 - Accrued Liabilities (Details) - Warranty Reserve Roll-Forward (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Warranty Reserve Roll-Forward [Abstract]
Balance at beginning of period	$ 275	$ 573	$ 331	$ 561
Warranty provision for product sales	113	117	215	219
Settlements made	(3)	(118)	(95)	(124)
Unused warranty provision	(51)	(129)	(117)	(213)
Balance at end of period	$ 334	$ 443	$ 334	$ 443