Fair Value and Derivative Instruments - Impact of Foreign Exchange Derivattive Contracts Designated as Cash Flow Hedges (Details) - Foreign exchange forward contracts - Designated as Hedging Instrument - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 27, 2020	Jun. 29, 2019	Jun. 27, 2020	Jun. 29, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Recognized in OCI on Derivative (Effective Portion)				$ 213
Amount of Gain or (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	$ 191	$ 183	$ 372	241
Other Comprehensive Income (Loss), Derivative, Excluded Component, Increase (Decrease), before Adjustments and Tax	52	213	126
Cost of revenues
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	139	139	258	171
Research and development
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	17	12	35	19
Selling, general and administrative
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain or (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	$ 35	$ 32	$ 79	$ 51