Note 3 - Significant Customers, Concentration of Credit Risk, and Geographic Information - Geographic Activity, Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Net revenues	$ 2,755	$ 2,666	$ 7,461	$ 7,186
Geographic Concentration Risk [Member] | Sales Revenue, Net [Member]
Net revenues	$ 2,755	$ 2,666	$ 7,461	$ 7,186
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	$ 1,962	$ 1,394	$ 4,785	$ 3,852
Percentage of net revenues	71.20%	52.30%	64.10%	53.60%
Europe [Member] | Geographic Concentration Risk [Member] | Sales Revenue, Net [Member]
Net revenues	$ 356	$ 557	$ 1,447	$ 1,518
Percentage of net revenues	12.90%	20.90%	19.40%	21.10%
Asia Pacific [Member] | Geographic Concentration Risk [Member] | Sales Revenue, Net [Member]
Net revenues	$ 396	$ 686	$ 1,113	$ 1,724
Percentage of net revenues	14.40%	25.70%	14.90%	24.00%
Other Geographic Areas [Member] | Geographic Concentration Risk [Member] | Sales Revenue, Net [Member]
Net revenues	$ 41	$ 29	$ 116	$ 92
Percentage of net revenues	1.50%	1.10%	1.60%	1.30%