Schedule of Fair Value of Financial Assets and Liabilities Measured on Recurring Basis (Detail) - USD ($) $ in Thousands	Jul. 02, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	$ 1,021,839	$ 1,304,867
U.S. Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	812,477	900,038
Corporate Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	64,453	100,153
Certificates of Deposit and Time Deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	22,253	82,133
Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	73,275	161,630
U.S. Government Agency Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	28,121	42,014
Equity And Debt Mutual Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	20,675	18,171
Non-U.S. Government Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	585	728
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Total	1,620,188	1,612,751
Derivative assets	23	1
Total	1,620,211	1,612,752
Contingent consideration	39,415	38,332
Derivative liabilities	304	131
Total	39,719	38,463
Fair Value, Measurements, Recurring | Cash
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash and cash equivalents	295,337	214,722
Fair Value, Measurements, Recurring | Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash and cash equivalents	303,012	93,162
Fair Value, Measurements, Recurring | U.S. Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	812,477	900,038
Fair Value, Measurements, Recurring | Corporate Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	64,453	100,153
Fair Value, Measurements, Recurring | Certificates of Deposit and Time Deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	22,253	82,133
Fair Value, Measurements, Recurring | Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	73,275	161,630
Fair Value, Measurements, Recurring | U.S. Government Agency Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	28,121	42,014
Fair Value, Measurements, Recurring | Equity And Debt Mutual Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	20,675	18,171
Fair Value, Measurements, Recurring | Non-U.S. Government Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	585	728
Quoted Prices in Active Markets for Identical Instruments (Level 1) | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Total	495,305	270,351
Total	495,305	270,351
Quoted Prices in Active Markets for Identical Instruments (Level 1) | Fair Value, Measurements, Recurring | Cash
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash and cash equivalents	295,337	214,722
Quoted Prices in Active Markets for Identical Instruments (Level 1) | Fair Value, Measurements, Recurring | Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash and cash equivalents	179,293	37,458
Quoted Prices in Active Markets for Identical Instruments (Level 1) | Fair Value, Measurements, Recurring | Equity And Debt Mutual Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	20,675	18,171
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Total	1,124,883	1,342,400
Derivative assets	23	1
Total	1,124,906	1,342,401
Derivative liabilities	304	131
Total	304	131
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Cash and cash equivalents	123,719	55,704
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | U.S. Treasury Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	812,477	900,038
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | Corporate Debt Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	64,453	100,153
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | Certificates of Deposit and Time Deposits
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	22,253	82,133
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	73,275	161,630
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | U.S. Government Agency Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	28,121	42,014
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | Non-U.S. Government Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Available for sale securities	585	728
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Contingent consideration	39,415	38,332
Total	$ 39,415	$ 38,332