Schedule of Carrying Amounts and Fair Values of Financial Instruments (Detail) - USD ($) $ in Thousands	Oct. 04, 2015	Dec. 31, 2014	Sep. 28, 2014	Dec. 31, 2013
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Cash and cash equivalents	$ 294,217	$ 294,256	$ 211,704	$ 341,638
Marketable securities	782,941	1,004,576
Contingent consideration	14,447	895
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Cash and cash equivalents	294,217	294,256
Marketable securities	782,941	1,004,576
Derivative assets	109	220
Contingent consideration	34,595	3,350
Derivative liabilities	97	369
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Cash and cash equivalents	294,217	294,256
Marketable securities	782,941	1,004,576
Derivative assets	109	220
Contingent consideration	34,595	3,350
Derivative liabilities	$ 97	$ 369