Nature of Business, Basis of Presentation and Significant Accounting Policies - Textual (Details) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 30, 2017 USD ($) Customer shares	Dec. 31, 2016 USD ($) Customer shares	Dec. 26, 2015 USD ($) Customer shares
Accounting Policies [Line Items]
Fiscal year duration	364 days	371 days	364 days
Products revenues	$ 214,877	$ 185,066	$ 146,945
Cost of products revenues	100,910	85,391	76,224
Service revenues	43,744	36,063	40,422
Cost of service revenues	20,804	20,160	19,450
Foreign currency transaction gain (loss)	$ (600)	(400)	500
Maximum period of delivery to customers	6 months
Maximum period services are provided over the fixed arrangement term	12 months
Product warranty period	12 months
Advertising costs	$ 200	$ 200	$ 300
Potential dilutive common stock equivalents, using treasury stock method | shares	585	498	316
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%	73.00%	69.00%
Stock Options [Member]
Accounting Policies [Line Items]
Potential dilutive common stock equivalents, using treasury stock method | shares	600	500	300
Reclassification [Member]
Accounting Policies [Line Items]
Products revenues	$ 12,100	$ 11,000
Cost of products revenues	$ 2,700	$ 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