Note 11 - Business Segment, Geographic and Concentration Risk Information - Product Line Sales (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jul. 01, 2016	Jun. 30, 2017	Jul. 01, 2016
Sales revenue, net	$ 7,223	$ 2,554	$ 12,263	$ 4,616
Algovita [Member]
Sales revenue, net	5,491	569	8,878	984
Neural Interface Components and Systems [Member]
Sales revenue, net	1,174	1,321	2,375	2,457
Development and Engineering Services [Member]
Sales revenue, net	$ 558	$ 664	$ 1,010	$ 1,175