Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2017	Dec. 31, 2016
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Short-term marketable securities	$ 4,982	$ 10,308
Level 1
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Short-term marketable securities	4,982	10,230
Foreign currency forward exchange contracts, net	0	0
Total fair value of financial instruments	4,982	10,230
Unrealized loss	100	200
Level 2
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Short-term marketable securities	0	78
Foreign currency forward exchange contracts, net	77	184
Total fair value of financial instruments	77	262
Level 3
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Short-term marketable securities	0	0
Foreign currency forward exchange contracts, net	0	0
Total fair value of financial instruments	0	0
Total
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Short-term marketable securities	4,982	10,308
Foreign currency forward exchange contracts, net	77	184
Total fair value of financial instruments	$ 5,059	$ 10,492