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. 01, 2018	Jul. 02, 2017	Jul. 01, 2018	Jul. 02, 2017
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 3,122	$ 3,026	$ 5,886	$ 6,196
Asia Pacific (1)
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	1,372	1,676	2,293	3,409
North America (2)
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	1,474	1,090	3,039	2,223
Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	276	260	554	564
Japan
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 632	$ 370	$ 1,000	$ 866
Percentage of total revenue	20.00%	12.00%	17.00%	14.00%
China
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenue	$ 466	$ 356	$ 602	$ 667
Percentage of total revenue	15.00%	12.00%	10.00%	11.00%
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Percentage of total revenue	46.00%	34.00%	50.00%	35.00%
Total revenue	$ 1,400	$ 1,000	$ 3,000	$ 2,200