Fair Value Measurements - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Detail) - USD ($) $ in Thousands	Jul. 02, 2017	Dec. 31, 2016
Assets:
Money market instruments	$ 3,554	$ 2,334
Financial assets at fair value	697,060
Corporate Bonds
Assets:
Financial assets at fair value	325,159
Treasury Bills
Assets:
Financial assets at fair value	152,563
Asset-Backed Securities
Assets:
Financial assets at fair value	87,260
Euro Liquidity Fund
Assets:
Financial assets at fair value	79,256
Sovereign Bonds
Assets:
Financial assets at fair value	30,933
Agency Bonds
Assets:
Financial assets at fair value	13,412
Municipal Bonds
Assets:
Financial assets at fair value	8,477
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Measurements, Recurring
Assets:
Money market instruments	3,554
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring
Assets:
Money market instruments	0
Cash flow hedge forward contracts	71
Economic hedge forward contracts	0
Liabilities:
Economic hedge forward contracts	4
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | Corporate Bonds
Assets:
Financial assets at fair value	325,159
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | Treasury Bills
Assets:
Financial assets at fair value	152,563
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | Asset-Backed Securities
Assets:
Financial assets at fair value	87,260
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | Euro Liquidity Fund
Assets:
Financial assets at fair value	79,256
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | Sovereign Bonds
Assets:
Financial assets at fair value	30,933
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | Agency Bonds
Assets:
Financial assets at fair value	13,412
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring | Municipal Bonds
Assets:
Financial assets at fair value	8,477
Fair Value, Inputs, Level 3 | Fair Value, Measurements, Recurring
Liabilities:
Contingent consideration liabilities	$ 3,959