Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) (USD $)	Jun. 29, 2012		Sep. 30, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Money market funds	$ 22,600,000		$ 1,300,000
Corporate debt security	47,200,000		19,200,000
Derivative assets	600,000
Option to purchase a company	1,400,000		1,400,000
Total assets measured at fair value	71,800,000		21,900,000
Contingent consideration	(9,100,000)		(100,000)
Total liabilities measured at fair value	(9,100,000)		(100,000)
Cash and cash equivalents	21,500,000		200,000
Short-term investment	47,155,000	[1]	19,205,000	[1],[2]
Prepaid expenses and other current assets	600,000
Other assets	2,500,000		2,500,000
Total assets measured at fair value	71,800,000		21,900,000
Accrued liabilities	(1,900,000)
Other long-term liabilities	(7,200,000)		(100,000)
Total liabilities measured at fair value	(9,100,000)		(100,000)
Quoted Prices in Active Markets for Identical Instruments (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Money market funds	22,600,000		1,300,000
Corporate debt security	0		0
Derivative assets	0
Option to purchase a company	0		0
Total assets measured at fair value	22,600,000		1,300,000
Contingent consideration	0		0
Total liabilities measured at fair value	0		0
Cash and cash equivalents	21,500,000		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	22,600,000		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
Money market funds	0		0
Corporate debt security	0		0
Derivative assets	600,000
Option to purchase a company	0		0
Total assets measured at fair value	600,000		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	600,000
Other assets	0		0
Total assets measured at fair value	600,000		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
Money market funds	0		0
Corporate debt security	47,200,000		19,200,000
Derivative assets	0
Option to purchase a company	1,400,000		1,400,000
Total assets measured at fair value	48,600,000		20,600,000
Contingent consideration	(9,100,000)		(100,000)
Total liabilities measured at fair value	(9,100,000)		(100,000)
Cash and cash equivalents	0		0
Short-term investment	47,155,000		19,205,000
Prepaid expenses and other current assets	0
Other assets	1,400,000		1,400,000
Total assets measured at fair value	48,600,000		20,600,000
Accrued liabilities	(1,900,000)
Other long-term liabilities	(7,200,000)		(100,000)
Total liabilities measured at fair value	$ (9,100,000)		$ (100,000)

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

[2] The condensed consolidated balance sheet as of September 30, 2011 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.