Related Party Transactions - Additional Information (Detail) (USD $)	1 Months Ended	12 Months Ended
Oct. 31, 2013	Sep. 26, 2014	Sep. 27, 2013	Sep. 28, 2012
Related Party Transactions [Abstract]
Ownership interest in dpiX Holding LLC		40.00%
dpiX Holding LLC's ownership interest in dpiX LLC		100.00%
Income (Loss) on equity investment in affiliate		$ (822,000)	$ 2,461,000	$ 245,000
Carrying value of the equity investment in dpiX Holding		49,700,000	49,700,000
Purchases of glass transistor arrays from dpiX		20,900,000	25,900,000	14,500,000
Percentage of manufacturing capacity	50.00%
Percentage of fixed costs	50.00%
Fixed Cost Commitments		$ 4,300,000

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

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- Definition

This item represents the entity's proportionate share for the period of the net income (loss) of its investee (such as unconsolidated subsidiaries and joint ventures) to which the equity method of accounting is applied. This item includes income or expense related to stock-based compensation based on the investor's grant of stock to employees of an equity method investee.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

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-Subparagraph (b)

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Reference 2: http://www.xbrl.org/2003/role/presentationRef

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Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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Reference 4: http://www.xbrl.org/2003/role/presentationRef

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Purchases during the period (excluding transactions that are eliminated in consolidated or combined financial statements) with related party.

+ References

No definition available.

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The amount of fixed manufacturing costs required to be paid during the fiscal year.

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No definition available.

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The percentage of fixed costs as defined in the agreement and determined at the beginning of each calendar year that the entity is required to pay.

+ References

No definition available.

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The percentage of manufacturing capacity that the entity has the guaranteed right to purchase up to.

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No definition available.

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- Definition

The percentage of dpiX Holding LLC's ownership interest in dpiX LLC.

+ References

No definition available.

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