Note 3 - Significant Customers, Concentration of Credit Risk, and Geographic Information - Geographic Activity, Revenue (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2015
Net revenues	$ 2,267	$ 2,370		$ 4,706	$ 4,520
Geographic Concentration Risk [Member] | Sales Revenue, Net [Member]
Net revenues		$ 2,267	$ 2,370		$ 4,706	$ 4,520
Percentage of net revenues		100.00%	100.00%		100.00%	100.00%
North America [Member] | Geographic Concentration Risk [Member] | Sales Revenue, Net [Member]
Net revenues		$ 1,279	$ 1,207		$ 2,822	$ 2,458
Percentage of net revenues		56.40%	50.90%		60.00%	54.40%
Europe [Member] | Geographic Concentration Risk [Member] | Sales Revenue, Net [Member]
Net revenues		$ 622	$ 473		$ 1,092	$ 961
Percentage of net revenues		27.50%	20.00%		23.20%	21.30%
Asia Pacific [Member] | Geographic Concentration Risk [Member] | Sales Revenue, Net [Member]
Net revenues		$ 313	$ 636		$ 717	$ 1,038
Percentage of net revenues		13.80%	26.80%		15.20%	23.00%
Other Geographic Areas [Member] | Geographic Concentration Risk [Member] | Sales Revenue, Net [Member]
Net revenues		$ 53	$ 54		$ 75	$ 63
Percentage of net revenues		2.30%	2.30%		1.60%	1.30%