Note 2 - Intangible Assets - Aggregate Intangible Asset Amortization Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jul. 01, 2016	Jun. 30, 2017	Jul. 01, 2016
Intangible asset amortization expense	$ 72	$ 67	$ 144	$ 135
Cost of Sales [Member]
Intangible asset amortization expense	31	27	63	55
Selling, General and Administrative Expenses [Member]
Intangible asset amortization expense	$ 41	$ 40	$ 81	$ 80