Fair Value - Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis (Detail) (Fair Value, Measurements, Recurring [Member], USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Assets:
Total assets	$ 23,528	$ 9,508
Liabilities:
Derivative instruments	350	78
Acquisition-related contingent consideration	8,032
Total liabilities	8,382	78
Money market funds [Member]
Assets:
Total assets	4,295	5,261
Commercial paper [Member]
Assets:
Total assets	2,598	3,247
U.S. government agencies and securities [Member]
Assets:
Total assets	4,145	1,000
Corporate bonds [Member]
Assets:
Total assets	12,490
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets:
Total assets	4,145	1,000
Liabilities:
Derivative instruments
Acquisition-related contingent consideration
Total liabilities
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Money market funds [Member]
Assets:
Total assets
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Commercial paper [Member]
Assets:
Total assets
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | U.S. government agencies and securities [Member]
Assets:
Total assets	4,145	1,000
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Corporate bonds [Member]
Assets:
Total assets
Significant Other Observable Inputs (Level 2) [Member]
Assets:
Total assets	19,383	8,508
Liabilities:
Derivative instruments
Acquisition-related contingent consideration
Total liabilities
Significant Other Observable Inputs (Level 2) [Member] | Money market funds [Member]
Assets:
Total assets	4,295	5,261
Significant Other Observable Inputs (Level 2) [Member] | Commercial paper [Member]
Assets:
Total assets	2,598	3,247
Significant Other Observable Inputs (Level 2) [Member] | U.S. government agencies and securities [Member]
Assets:
Total assets
Significant Other Observable Inputs (Level 2) [Member] | Corporate bonds [Member]
Assets:
Total assets	12,490
Significant Other Unobservable Inputs (Level 3) [Member]
Assets:
Total assets
Liabilities:
Derivative instruments	350	78
Acquisition-related contingent consideration	8,032
Total liabilities	8,382	78
Significant Other Unobservable Inputs (Level 3) [Member] | Money market funds [Member]
Assets:
Total assets
Significant Other Unobservable Inputs (Level 3) [Member] | Commercial paper [Member]
Assets:
Total assets
Significant Other Unobservable Inputs (Level 3) [Member] | U.S. government agencies and securities [Member]
Assets:
Total assets
Significant Other Unobservable Inputs (Level 3) [Member] | Corporate bonds [Member]
Assets:
Total assets