Fair Value Measurements (Summary Of Valuation Of Company's Financial Instruments By Various Levels) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 28, 2014		Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair value	$ 123,181		$ 137,345
Liabilities, Fair value	549		381
Quoted Market Prices In Active Markets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair value	120,187		136,440
Liabilities, Fair value	0		0
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair value	2,994		905
Liabilities, Fair value	549		381
Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair value	0		0
Liabilities, Fair value	0		0
Foreign Currency Forward Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair value	2,994	[1]	905	[1]
Liabilities, Fair value	549	[2]	381	[2]
Foreign Currency Forward Contracts [Member] | Quoted Market Prices In Active Markets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair value	0	[1]	0	[1]
Liabilities, Fair value	0	[2]	0	[2]
Foreign Currency Forward Contracts [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair value	2,994	[1]	905	[1]
Liabilities, Fair value	549	[2]	381	[2]
Foreign Currency Forward Contracts [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair value	0	[1]	0	[1]
Liabilities, Fair value	0	[2]	0	[2]
Money Market Funds [Member] | Cash Equivalents [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair value	19,359		31,295
Money Market Funds [Member] | Cash Equivalents [Member] | Quoted Market Prices In Active Markets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair value	19,359		31,295
Money Market Funds [Member] | Cash Equivalents [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair value	0		0
Money Market Funds [Member] | Cash Equivalents [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair value	0		0
U.S. Treasuries [Member] | Available-For-Sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair value	99,985	[3]	104,601	[3]
U.S. Treasuries [Member] | Available-For-Sale Securities [Member] | Quoted Market Prices In Active Markets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair value	99,985	[3]	104,601	[3]
U.S. Treasuries [Member] | Available-For-Sale Securities [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair value	0	[3]	0	[3]
U.S. Treasuries [Member] | Available-For-Sale Securities [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair value	0	[3]	0	[3]
Certificates Of Deposits [Member] | Available-For-Sale Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair value	166	[3]	159	[3]
Certificates Of Deposits [Member] | Available-For-Sale Securities [Member] | Quoted Market Prices In Active Markets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair value	166	[3]	159	[3]
Certificates Of Deposits [Member] | Available-For-Sale Securities [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair value	0	[3]	0	[3]
Certificates Of Deposits [Member] | Available-For-Sale Securities [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair value	0	[3]	0	[3]
Mutual Funds [Member] | Trading Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair value	677	[3]	385	[3]
Mutual Funds [Member] | Trading Securities [Member] | Quoted Market Prices In Active Markets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair value	677	[3]	385	[3]
Mutual Funds [Member] | Trading Securities [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair value	0	[3]	0	[3]
Mutual Funds [Member] | Trading Securities [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair value	$ 0	[3]	$ 0	[3]

[1] Included in prepaid expenses and other current assets on the Company’s unaudited condensed consolidated balance sheet.

[2] Included in other accrued liabilities on the Company’s unaudited condensed consolidated balance sheet.

[3] Included in short-term investments on the Company’s unaudited condensed consolidated balance sheet.