Fair Value Measurements

6 Months Ended

Mar. 30, 2012

Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]

Fair value is the exchange price that would be received for an asset or paid to transfer a liability in the principal or most advantageous market for the asset or liability, in an orderly transaction between market participants at the measurement date. We minimize the use of unobservable inputs and use observable market data, if available, when determining fair value. We classify our inputs to measure fair value using the following three-level hierarchy:


Level 1:	Quoted prices in active markets at the measurement date for identical assets and liabilities.


Level 2:	Prices may be based upon quoted prices in active markets or inputs not quoted on active markets but are corroborated by market data.


Level 3:	Unobservable inputs are used when little or no market data is available and reflect management’s estimates of assumptions that market participants would use in pricing the asset or liability.

Financial assets and liabilities carried at fair value are classified below:



	September 30, 2011
	Level 1		Level 2		Level 3		Total
	(in thousands)
Assets:
Investments held in supplemental retirement plan (1)	$	1,891	$	—	$	—	$	1,891
Money market funds (2)	142,038		—		—		142,038
Corporate bonds (3)	—		176,958		—		176,958
Municipal debt securities (3)	—		472,201		—		472,201
U.S. agency securities (2), (3)	29,919		—		—		29,919
Total	$	173,848	$	649,159	$	—	$	823,007


(1)	These assets are included within prepaid expenses and other current assets and within other non-current assets.


(2)	These assets are included within cash and cash equivalents.


(3)	These assets are included within short-term investments and within long-term investments.



	September 30, 2011
	Level 1		Level 2		Level 3		Total
	(in thousands)
Liabilities:
Investments held in supplemental retirement plan (1)	$	1,891	$	—	$	—	$	1,891
Total	$	1,891	$	—	$	—	$	1,891


(1)	These liabilities are included within accrued compensation and benefits and within other non-current liabilities.



	March 30, 2012
	Level 1		Level 2		Level 3		Total
	(in thousands)
Assets:
Investments held in supplemental retirement plan (1)	$	2,137	$	—	$	—	$	2,137
Money market funds (2)	264,366		—		—		264,366
Commercial paper (3)	—		20,984		—		20,984
Corporate bonds (4)	—		125,092		—		125,092
Municipal debt securities (4)	—		389,371		—		389,371
U.S. agency securities (4)	25,092		—		—		25,092
Total	$	291,595	$	535,447	$	—	$	827,042


(1)	These assets are included within prepaid expenses and other current assets and within other non-current assets.


(2)	These assets are included within cash and cash equivalents.


(3)	These assets are included within short-term investments.


(4)	These assets are included within short-term investments and within long-term investments.



	March 30, 2012
	Level 1		Level 2		Level 3		Total
	(in thousands)
Liabilities:
Investments held in supplemental retirement plan (1)	$	2,137	$	—	$	—	$	2,137
Total	$	2,137	$	—	$	—	$	2,137


(1)	These liabilities are included within accrued compensation and benefits and within other non-current liabilities.

We base the fair value of our Level 1 financial instruments, which are traded in active markets, using quoted market prices for identical instruments. Our Level 1 financial instruments include money market funds, U.S. agency securities, U.S. government bonds, and mutual fund investments held in our supplemental retirement plan.

We obtain the fair value of our Level 2 financial instruments from a professional pricing service, which may use quoted market prices for identical or comparable instruments, or model driven valuations using observable market data or inputs corroborated by observable market data.

To validate the fair value determination provided by our primary pricing service, we perform quality controls over values received which include comparing our pricing service provider’s assessment of the fair values of our investment securities against the fair values of our investment securities obtained from another independent source, reviewing the pricing movement in the context of overall market trends, and reviewing trading information from our investment managers. In addition, we assess the inputs and methods used in determining the fair value in order to determine the classification of securities in the fair value hierarchy.

We did not own any Level 3 financial assets or liabilities as of September 30, 2011 or March 30, 2012.

- Definition

Tabular disclosure of the fair value measurement of assets and liabilities which includes [financial] instruments measured at fair value that are classified in stockholders' equity. Such assets and liabilities may be measured on a recurring or nonrecurring basis. The disclosures which may be required or desired include: (1) for assets and liabilities measured on a recurring basis, disclosure may include: (a) the fair value measurements at the reporting date; (b) the level within the fair value hierarchy in which the fair value measurements in their entirety fall, segregating fair value measurements using quoted prices in active markets for identical assets or liabilities (Level 1), significant other observable inputs (Level 2), and significant unobservable inputs (Level 3); (c) for fair value measurements using significant unobservable inputs (Level 3), a reconciliation of the beginning and ending balances, separately presenting changes during the period attributable to the following: (i) total gains or losses for the period (realized and unrealized), segregating those gains or losses included in earnings (or changes in net assets), and a description of where those gains or losses included in earnings (or changes in net assets) are reported in the statement of income (or activities); (ii) purchases, sales, issuances, and settlements (net); (iii) transfers in and transfers out of Level 3 (for example, transfers due to changes in the observability of significant inputs); (d) the amount of the total gains or losses for the period in subparagraph (c) (i) above included in earnings (or changes in net assets) that are attributable to the change in unrealized gains or losses relating to those assets and liabilities still held at the reporting date and a description of where those unrealized gains or losses are reported in the statement of income (or activities); (e) the valuation technique(s) used to measure fair value and a discussion of changes in valuation techniques, if any, during the period and (2) for assets and liabilities that are measured at fair value on a nonrecurring basis (for example, impaired assets) disclosure may include, in addition to (a) above: (a) the reasons for the fair value measurements recorded; (b) the same as (b) above; (c) for fair value measurements using significant unobservable inputs (Level 3), a description of the inputs and the information used to develop the inputs; and (d) the valuation technique(s) used to measure fair value and a discussion of changes, if any, in the valuation technique(s) used to measure similar assets and/or liabilities in prior periods. Where the quoted price in an active market for the identical liability is not available, the Level 1 input is the quoted price of an identical liability when traded as an asset.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19279-110258

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 157

-Paragraph 32

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 157

-Paragraph 33

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 107

-Paragraph 10

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19296-110258

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19207-110258

Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 157

-Paragraph 6

-Footnote 4

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 8: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19190-110258

+ Details