Investments (Tables)

3 Months Ended

Mar. 29, 2014

Investments, Debt and Equity Securities [Abstract]

Available-for-sale Securities

The following table summarizes our investments:

	March 29, 2014								December 31, 2013
	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	$	17,988	$	—	$	—	$	17,988	$	3,199	$	—	$	—	$	3,199
Money market funds	31,408		—		—		31,408		42,994		—		—		42,994
U.S. treasury bills and notes	6,028		5		—		6,033		6,067		5		—		6,072
Securities and obligations of U.S. government agencies	191,215		34		87		191,162		194,254		30		70		194,214
Total	$	246,639	$	39	$	87	$	246,591	$	246,514	$	35	$	70	$	246,479

Fair Value, by Balance Sheet Grouping

The following table identifies the balance sheet classifications of our investments:

(In thousands)	March 29, 2014		December 31, 2013
Cash equivalents	$	35,407	$	42,994
Short-term investments	211,184		203,485
Investments, at estimated fair value	$	246,591	$	246,479

Investments Classified by Contractual Maturity Date

The gross amortized cost and estimated fair value of our investments at March 29, 2014 and December 31, 2013, 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.

	March 29, 2014				December 31, 2013
(In thousands)	Gross Amortized Cost		Fair Value		Gross Amortized Cost		Fair Value
Due in one year or less	$	216,560	$	216,537	$	223,456	$	223,413
Due after one year through five years	30,079		30,054		23,059		23,066
Total	$	246,639	$	246,591	$	246,515	$	246,479

Schedule of Temporary Impairment Losses, Investments

The following table provides the breakdown of the cash equivalents and investments with unrealized losses at March 29, 2014:

	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	$	47,775	$	87	$	47,775	$	87
Total	$	47,775	$	87	$	47,775	$	87

The following table provides the breakdown of the cash equivalents and investments with unrealized losses at December 31, 2013:

	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	$	71,979	$	70	$	71,979	$	70
Total	$	71,979	$	70	$	71,979	$	70