Derivative Financial Instruments (Schedule of Company's Derivative Instruments on Other Comprehensive Income and the Consolidated Statement of Operations) (Details) - Cash Flow Hedges - Designated as Hedging Instrument - Foreign currency forward contracts - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jul. 01, 2018	Jul. 02, 2017	Jul. 01, 2018	Jul. 02, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Gains (Losses) Recognized in OCI - Effective Portion		$ 1,680	$ (6,935)	$ 180	$ (7,052)
Gains (Losses) Reclassified from OCI into Income - Effective Portion	[1]	1,556	(932)	(636)	648
Net revenue
Derivative Instruments, Gain (Loss) [Line Items]
Gains (Losses) Reclassified from OCI into Income - Effective Portion	[1]	1,783	(1,008)	(785)	1,027
Cost of revenue
Derivative Instruments, Gain (Loss) [Line Items]
Gains (Losses) Reclassified from OCI into Income - Effective Portion	[1]	(7)	(1)	(1)	(14)
Research and development
Derivative Instruments, Gain (Loss) [Line Items]
Gains (Losses) Reclassified from OCI into Income - Effective Portion	[1]	(13)	(55)	86	(74)
Sales and marketing
Derivative Instruments, Gain (Loss) [Line Items]
Gains (Losses) Reclassified from OCI into Income - Effective Portion	[1]	(157)	115	73	(249)
General and administrative
Derivative Instruments, Gain (Loss) [Line Items]
Gains (Losses) Reclassified from OCI into Income - Effective Portion	[1]	$ (50)	$ 17	$ (9)	$ (42)

[1] Refer to Note 10, Stockholders' Equity, which summarizes the accumulated other comprehensive income activity related to derivatives.