Investments (Tables)

9 Months Ended

Sep. 29, 2012

Investments, Debt and Equity Securities [Abstract]

Available-for-sale Securities

The following table summarizes our investments:

	September 29, 2012								December 31, 2011
	Amortized Cost		Accumulated Other Comprehensive Income				Estimated Fair  Value		Amortized Cost		Accumulated Other Comprehensive Income				Estimated Fair  Value
Available-for-sale securities (in thousands)			Gains		Losses						Gains		Losses
Commercial paper	$	17,997	$	—	$	—	$	17,997	$	9,996	$	—	$	—	$	9,996
Money market funds	5,318		—		—		5,318		6,706		—		—		6,706
U.S. corporate debt securities	—		—		—		—		1,441		—		1		1,440
U.S. treasury bills and notes	4,022		4		—		4,026		3,908		5		—		3,913
Securities and obligations of U.S. government agencies	198,546		60		59		198,547		162,703		37		71		162,669
Total	$	225,883	$	64	$	59	$	225,888	$	184,754	$	42	$	72	$	184,724

Fair Value, by Balance Sheet Grouping

The following table identifies the balance sheet classifications of our investments at September 29, 2012 and December 31, 2011:

(In thousands)	September 29, 2012		December 31, 2011
Cash equivalents	$	19,317	$	15,557
Short-term investments	206,571		169,167
Investments, at estimated fair value	$	225,888	$	184,724

Investments Classified by Contractual Maturity Date

The gross amortized cost and estimated fair value of our investments at September 29, 2012 and December 31, 2011, by contractual maturity, are shown below. Expected maturities will differ from contractual maturities because the issuers of the securities may have the right to prepay obligations without prepayment penalties.

	September 29, 2012				December 31, 2011
(In thousands)	Gross Amortized Cost		Fair Value		Gross Amortized Cost		Fair Value
Due in one year or less	$	169,310	$	169,302	$	153,346	$	153,328
Due after one year through five years	56,573		56,586		31,408		31,396
Total	$	225,883	$	225,888	$	184,754	$	184,724

Schedule of Temporary Impairment Losses, Investments

The following table provides the breakdown of the cash equivalents and investments with unrealized losses at September 29, 2012:

	In Loss Position for Less Than 12 Months				Total
(In thousands)	Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses
Securities and obligations of U.S. government agencies	28,508		59		28,508		59
Total	$	28,508	$	59	$	28,508	$	59

The following table provides the breakdown of the cash equivalents and investments with unrealized losses at December 31, 2011:

	In Loss Position for Less Than 12 Months				Total
(In thousands)	Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses
U.S. Corporate debt securities	$	1,440	$	1	$	1,440	$	1
Securities and obligations of U.S. government agencies	28,173		71		28,173		71
Total	$	29,613	$	72	$	29,613	$	72