Fair Value Measurements (Details) (USD $) In Thousands, unless otherwise specified	Mar. 29, 2014		Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total, fair value	$ 246,591		$ 246,479
Fair Value, Measurements, Recurring | Total
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net current assets and current liabilities, fair value	246,589		246,472
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net current assets and current liabilities, fair value	37,441		49,066
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net current assets and current liabilities, fair value	209,148		197,406
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net current assets and current liabilities, fair value	0		0
Commercial papers
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total, fair value	17,988		3,199
Money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total, fair value	31,408		42,994
U.S. treasury bills and notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total, fair value	6,033		6,072
Securities and obligations of U.S. government agencies
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total, fair value	191,162		194,214
Cash and Cash Equivalents and Short-term Investments | Commercial papers | Fair Value, Measurements, Recurring | Total
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total, fair value	17,988	[1]	3,199	[1]
Cash and Cash Equivalents and Short-term Investments | Commercial papers | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total, fair value	0	[1]	0	[1]
Cash and Cash Equivalents and Short-term Investments | Commercial papers | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total, fair value	17,988	[1]	3,199	[1]
Cash and Cash Equivalents and Short-term Investments | Commercial papers | Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total, fair value	0	[1]	0	[1]
Cash and Cash Equivalents and Short-term Investments | Money market funds | Fair Value, Measurements, Recurring | Total
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total, fair value	31,408	[1]	42,994	[1]
Cash and Cash Equivalents and Short-term Investments | Money market funds | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total, fair value	31,408	[1]	42,994	[1]
Cash and Cash Equivalents and Short-term Investments | Money market funds | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total, fair value	0	[1]	0	[1]
Cash and Cash Equivalents and Short-term Investments | Money market funds | Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total, fair value	0	[1]	0	[1]
Cash and Cash Equivalents and Short-term Investments | U.S. treasury bills and notes | Fair Value, Measurements, Recurring | Total
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total, fair value	6,033	[1]	6,072	[1]
Cash and Cash Equivalents and Short-term Investments | U.S. treasury bills and notes | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total, fair value	6,033	[1]	6,072	[1]
Cash and Cash Equivalents and Short-term Investments | U.S. treasury bills and notes | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total, fair value	0	[1]	0	[1]
Cash and Cash Equivalents and Short-term Investments | U.S. treasury bills and notes | Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total, fair value	0	[1]	0	[1]
Cash and Cash Equivalents and Short-term Investments | Securities and obligations of U.S. government agencies | Fair Value, Measurements, Recurring | Total
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total, fair value	191,162	[1]	194,214	[1]
Cash and Cash Equivalents and Short-term Investments | Securities and obligations of U.S. government agencies | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total, fair value	0	[1]	0	[1]
Cash and Cash Equivalents and Short-term Investments | Securities and obligations of U.S. government agencies | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total, fair value	191,162	[1]	194,214	[1]
Cash and Cash Equivalents and Short-term Investments | Securities and obligations of U.S. government agencies | Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total, fair value	0	[1]	0	[1]
Cash and Cash Equivalents and Short-term Investments | Available-for-sale securities | Fair Value, Measurements, Recurring | Total
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total, fair value	246,591	[1]	246,479	[1]
Cash and Cash Equivalents and Short-term Investments | Available-for-sale securities | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total, fair value	37,441	[1]	49,066	[1]
Cash and Cash Equivalents and Short-term Investments | Available-for-sale securities | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total, fair value	209,150	[1]	197,413	[1]
Cash and Cash Equivalents and Short-term Investments | Available-for-sale securities | Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total, fair value	0	[1]	0	[1]
Designated as Hedging Instrument | Foreign Exchange Forward | Fair Value, Measurements, Recurring | Total
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign currency derivatives, other current asset	3	[2]	12	[2]
Foreign currency derivatives, other current liabilities	(5)	[3]	(19)	[3]
Designated as Hedging Instrument | Foreign Exchange Forward | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign currency derivatives, other current asset	0	[2]	0	[2]
Foreign currency derivatives, other current liabilities	0	[3]	0	[3]
Designated as Hedging Instrument | Foreign Exchange Forward | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign currency derivatives, other current asset	3	[2]	12	[2]
Foreign currency derivatives, other current liabilities	(5)	[3]	(19)	[3]
Designated as Hedging Instrument | Foreign Exchange Forward | Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign currency derivatives, other current asset	0	[2]	0	[2]
Foreign currency derivatives, other current liabilities	$ 0	[3]	$ 0	[3]

[1] Included in cash and cash equivalents and short-term investments on our condensed consolidated balance sheets. See “Investments” in Note 6 for further details.

[2] Included in other current assets on our condensed consolidated balance sheets. Consisted of forward foreign exchange contracts for the Japanese yen. See “Derivative Instruments and Hedging” in Note 7 for further details.

[3] Included in other current liabilities on our condensed consolidated balance sheets. Consisted of forward foreign exchange contracts for the Japanese yen. See “Derivative Instruments and Hedging” in Note 7 for further details.