Note 7 - Goodwill, Intangible Assets and Long Term Assets - Amortization Expense for Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Oct. 01, 2017	Sep. 30, 2018	Oct. 01, 2017
Amortization of Intangible Assets	$ 97	$ 106	$ 300	$ 315
Research and Development Expense [Member]
Amortization of Intangible Assets	36	42	111	123
Selling, General and Administrative Expenses [Member]
Amortization of Intangible Assets	$ 61	$ 64	$ 189	$ 192