Cash Equivalents and Marketable Securities - Available-for-Sale Securities (Detail) (USD $)	Dec. 29, 2012	Sep. 29, 2012
Restricted Cash and Cash Equivalents Items [Line Items]
Available-for-sale securities, Cost	$ 4,992,709
Available-for-sale securities, Accrued Interest	32,137
Available-for-sale securities, Gross Unrealized Gains	15,861
Available-for-sale securities, Gross Unrealized Losses	6,605
Available-for-sale securities, Estimated Fair Value	5,034,102	6,009,304
Money market funds [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Available-for-sale securities, Cost	328,998
Available-for-sale securities, Accrued Interest
Available-for-sale securities, Gross Unrealized Gains
Available-for-sale securities, Gross Unrealized Losses
Available-for-sale securities, Estimated Fair Value	328,998
Certificates of deposit [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Available-for-sale securities, Cost	2,742,075
Available-for-sale securities, Accrued Interest	4,320
Available-for-sale securities, Gross Unrealized Gains
Available-for-sale securities, Gross Unrealized Losses	6,605
Available-for-sale securities, Estimated Fair Value	2,739,790
Municipal bonds [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Available-for-sale securities, Cost	1,921,636
Available-for-sale securities, Accrued Interest	27,817
Available-for-sale securities, Gross Unrealized Gains	15,861
Available-for-sale securities, Gross Unrealized Losses
Available-for-sale securities, Estimated Fair Value	$ 1,965,314

This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents Available-for-sale Securities which consist of all investments in certain debt and equity securities neither classified as trading or held-to-maturity securities. A debt security represents a creditor relationship with an enterprise. Debt securities include, among other items, US Treasury securities, US government securities, municipal securities, corporate bonds, convertible debt, commercial paper, and all securitized debt instruments. An equity security represents an ownership interest in an enterprise or the right to acquire or dispose of an ownership interest in an enterprise at fixed or determinable prices. Equity securities include, among other things, common stock, certain preferred stock, warrant rights, call options, and put options, but do not include convertible debt. An entity may opt to provide the reader with additional narrative text to better understand the nature of investments in debt and equity securities which are categorized as Available-for-sale.

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- Definition

This item represents the gross unrealized gains for securities, at a point in time, which are categorized neither as held-to-maturity nor trading securities.

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