Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) (USD $)	Sep. 28, 2012		Sep. 30, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds	$ 45,700,000		$ 1,300,000
Debt security	49,700,000		19,200,000
Derivative assets	800,000
Option to purchase a company	1,400,000		1,400,000
Total assets measured at fair value	97,600,000		21,900,000
Contingent consideration	(8,800,000)		(100,000)
Total liabilities measured at fair value	(8,800,000)		(100,000)
Cash and cash equivalents	44,600,000		200,000
Short-term investment	49,709,000	[1]	19,205,000	[1]
Prepaid expenses and other current assets	800,000
Other assets	2,500,000		2,500,000
Total assets measured at fair value	97,600,000		21,900,000
Accrued liabilities	(1,600,000)
Other long-term liabilities	(7,200,000)		(100,000)
Total liabilities measured at fair value	(8,800,000)		(100,000)
Quoted Prices in Active Markets for Identical Instruments (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds	45,700,000		1,300,000
Debt security	0		0
Derivative assets	0
Option to purchase a company	0		0
Total assets measured at fair value	45,700,000		1,300,000
Contingent consideration	0		0
Total liabilities measured at fair value	0		0
Cash and cash equivalents	44,600,000		200,000
Short-term investment	0		0
Prepaid expenses and other current assets	0
Other assets	1,100,000		1,100,000
Total assets measured at fair value	45,700,000		1,300,000
Accrued liabilities	0
Other long-term liabilities	0		0
Total liabilities measured at fair value	0		0
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds	0		0
Debt security	0		0
Derivative assets	800,000
Option to purchase a company	0		0
Total assets measured at fair value	800,000		0
Contingent consideration	0		0
Total liabilities measured at fair value	0		0
Cash and cash equivalents	0		0
Short-term investment	0		0
Prepaid expenses and other current assets	800,000
Other assets	0		0
Total assets measured at fair value	800,000		0
Accrued liabilities	0
Other long-term liabilities	0		0
Total liabilities measured at fair value	0		0
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds	0		0
Debt security	49,700,000		19,200,000
Derivative assets	0
Option to purchase a company	1,400,000		1,400,000
Total assets measured at fair value	51,100,000		20,600,000
Contingent consideration	(8,800,000)		(100,000)
Total liabilities measured at fair value	(8,800,000)		(100,000)
Cash and cash equivalents	0		0
Short-term investment	49,709,000		19,205,000
Prepaid expenses and other current assets	0
Other assets	1,400,000		1,400,000
Total assets measured at fair value	51,100,000		20,600,000
Accrued liabilities	(1,600,000)
Other long-term liabilities	(7,200,000)		(100,000)
Total liabilities measured at fair value	$ (8,800,000)		$ (100,000)

[1] Represents a loan to CPTC. See Note 16, "Variable Interest Entity."