Note 10 - Information Concerning Product Lines, Geographic Information and Revenue Concentration - Schedule of Revenue by Shipment Destination (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jul. 04, 2021	Jun. 28, 2020	Jul. 04, 2021	Jun. 28, 2020
Total revenue		$ 2,882	$ 2,196	$ 5,122	$ 4,354
Asia Pacific [Member]
Total revenue	[1]	1,075	779	1,828	1,185
North America [Member]
Total revenue	[2]	565	1,282	1,824	2,234
Europe [Member]
Total revenue		$ 1,242	$ 135	$ 1,470	$ 935

[1] Asia Pacific includes revenue from Japan of $917,000, or 32% of total revenue and $771,000 or 35% of total revenue for the quarters ended July 4, 2021 and June 28, 2020, respectively. For the six months ended July 4, 2021 and June 28,2020, revenue from Japan was $1.6 million, or 32% of total revenue, and $1.2 million, or 27% of total revenue,respectively.

[2] North America includes revenue from the United States of $562,000, or 19% of total revenue, and $1.3 million, or 58% of total revenue, for the three months ended July 4, 2021 and June 28, 2020, respectively. For the six months ended July 4, 2021 and June 28, 2020 revenue from the United States was $1.8 million, or 35% of total revenue, and $2.2 million,or 51% of total revenue, respectively.