Computation of Basic and Diluted Net Loss Per Common Share - Reconciliation of Numerator and Denominator of Basic and Diluted Net Loss Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jul. 01, 2017	Jun. 30, 2018	Jul. 01, 2017
Numerator:
Net loss	$ (3,280)	$ (2,750)	$ (6,883)	$ (4,616)
Denominator:
Weighted average shares of common stock (basic)	11,644	11,546	11,636	11,532
Weighted average shares of common stock (diluted)	11,644	11,546	11,636	11,532
Per share data:
Basic net loss per share	$ (0.28)	$ (0.24)	$ (0.59)	$ (0.40)
Diluted net loss per share	$ (0.28)	$ (0.24)	$ (0.59)	$ (0.40)