Related Party Transactions - Additional Information (Detail) (USD $)	1 Months Ended	3 Months Ended			6 Months Ended
	Jul. 27, 2012	Mar. 29, 2013	Dec. 28, 2012 Installment	Mar. 30, 2012	Mar. 29, 2013	Mar. 30, 2012	Sep. 28, 2012
Related Party Transaction [Line Items]
Ownership interest in dpiX Holding LLC		40.00%			40.00%
dpiX Holding LLC's ownership interest in dpiX LLC		100.00%			100.00%
Income (Loss) on equity investment in affiliate		$ (700,000)		$ (1,400,000)	$ (564,000)	$ (503,000)
Carrying value of the equity investment in dpiX Holding		46,700,000			46,700,000		45,500,000
Loan agreement, related party	8,800,000
Loan agreement, amendment date			December 2011
Related party loan agreement, interest rate			Prime plus 1%
Number of installment payment for principal with accrued and unpaid interest			2
Purchases of glass transistor arrays from dpiX		$ 5,300,000		$ 2,600,000	$ 16,100,000	$ 8,000,000