Nature of Business, Basis of Presentation and Significant Accounting Policies - Textual (Details) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($) Customer shares	Dec. 26, 2015 USD ($) Customer shares	Dec. 27, 2014 USD ($) Customer shares
Accounting Policies [Line Items]
Fiscal year duration	371 days	364 days	364 days
Products revenues	$ 185,066	$ 146,945	$ 133,589
Cost of products revenues	85,391	76,224	68,812
Service revenues	36,063	40,422	32,854
Cost of service revenues	20,160	19,450	19,086
Foreign currency transaction gain (loss)	$ (400)	500	100
Maximum period of delivery to customers	6 months
Maximum period services are provided over the fixed arrangement term	12 months
Maximum measurement period	1 year
Product warranty period	12 months
Advertising costs	$ 200	$ 300	$ 200
Potential dilutive common stock equivalents, using treasury stock method | shares	498	316	0
Anti-dilutive common stock equivalents excluded from calculation | shares			400
Number of Major Customer | Customer	5	5	5
Sales Revenue, Goods, Net [Member] | Customer Concentration Risk [Member]
Accounting Policies [Line Items]
Concentration of risk percentage	73.00%	69.00%	72.00%
Stock Options [Member]
Accounting Policies [Line Items]
Potential dilutive common stock equivalents, using treasury stock method | shares	500	300
Reclassification [Member]
Accounting Policies [Line Items]
Products revenues	$ 11,000
Cost of products revenues	$ 2,400
Service revenues		$ 7,900
Cost of service revenues		$ 3,000
Minimum [Member]
Accounting Policies [Line Items]
Fiscal year duration	364 days
Maximum [Member]
Accounting Policies [Line Items]
Fiscal year duration	371 days