Business Segments - Revenue Information by Geographic Region (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 02, 2016	Jul. 04, 2015	Jul. 02, 2016	Jul. 04, 2015
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenues	$ 11,908	$ 9,033	$ 23,839	$ 19,829
United States
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenues	6,923	5,391	12,771	10,972
Europe
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenues	2,297	1,366	4,588	3,680
Rest of Americas
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenues	762	539	1,382	1,535
Asia/Pacific Rim
Revenues From External Customers And Long Lived Assets [Line Items]
Total revenues	$ 1,926	$ 1,737	$ 5,098	$ 3,642