Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) (USD $)	Mar. 29, 2013		Sep. 28, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt security	$ 56,100,000		$ 49,700,000
Derivative assets	2,600,000		800,000
Option to purchase a company	1,400,000		1,400,000
Total assets measured at fair value	105,400,000		97,600,000
Contingent consideration	(7,900,000)		(8,800,000)
Total liabilities measured at fair value	(7,900,000)		(8,800,000)
Cash and cash equivalents	44,600,000		44,600,000
Short-term investment	56,137,000	[1]	49,709,000	[1],[2]
Prepaid expenses and other current assets	2,600,000		800,000
Other assets	2,100,000		2,500,000
Total assets measured at fair value	105,400,000		97,600,000
Accrued liabilities	(1,700,000)		(1,600,000)
Other long-term liabilities	(6,200,000)		(7,200,000)
Total liabilities measured at fair value	(7,900,000)		(8,800,000)
Money Market Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	45,300,000		45,700,000
Quoted Prices in Active Markets for Identical Instruments (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	45,300,000		45,700,000
Cash and cash equivalents	44,600,000		44,600,000
Other assets	700,000		1,100,000
Total assets measured at fair value	45,300,000		45,700,000
Quoted Prices in Active Markets for Identical Instruments (Level 1) | Money Market Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	45,300,000		45,700,000
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	2,600,000		800,000
Total assets measured at fair value	2,600,000		800,000
Prepaid expenses and other current assets	2,600,000		800,000
Total assets measured at fair value	2,600,000		800,000
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt security	56,100,000		49,700,000
Option to purchase a company	1,400,000		1,400,000
Total assets measured at fair value	57,500,000		51,100,000
Contingent consideration	(7,900,000)		(8,800,000)
Total liabilities measured at fair value	(7,900,000)		(8,800,000)
Short-term investment	56,137,000		49,709,000
Other assets	1,400,000		1,400,000
Total assets measured at fair value	57,500,000		51,100,000
Accrued liabilities	(1,700,000)		(1,600,000)
Other long-term liabilities	(6,200,000)		(7,200,000)
Total liabilities measured at fair value	$ (7,900,000)		$ (8,800,000)

[1] Represents a loan to CPTC. See Note 15, "Variable Interest Entity."

[2] The condensed consolidated balance sheet as of September 28, 2012 was derived from audited financial statements as of that date, but does not include all disclosures required by accounting principles generally accepted in the United States of America.