Business Segments and Geographical Information - Revenue Information by Geographic Region (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 30, 2017	Sep. 30, 2017	Jul. 01, 2017	Apr. 01, 2017	Dec. 31, 2016	Oct. 01, 2016	Jul. 02, 2016	Apr. 02, 2016	Dec. 30, 2017	Dec. 31, 2016	Jan. 02, 2016
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenues	$ 10,243	$ 10,865	$ 10,002	$ 10,483	$ 12,530	$ 9,789	$ 11,908	$ 11,931	$ 41,593	$ 46,158	$ 41,757
United States
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenues									23,017	25,171	23,952
Europe
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenues									8,097	9,567	7,968
Rest of Americas
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenues									2,319	2,800	2,676
Asia/Pacific Rim
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenues									$ 8,160	$ 8,620	$ 7,161