Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2011

Fair Value Measurements

Schedule of assets measured at fair value on a recurring basis

Below is a table of our assets that we measure at fair value on a recurring basis. For the following major security types, we break down the inputs used to measure fair value at June 30, 2011 (in thousands):

	Total		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Cash equivalents (1)	$	84,740	$	72,845	$	11,895	$	—
Corporate debt securities (2)	225,236		—		225,236		—
Debt securities issued by U.S. government agencies (2)	67,275		—		67,275		—
Debt securities issued by the U.S. Treasury (2)	6,523		6,523		—		—
Debt securities issued by states of the United States and political subdivisions of the states (2)	11,128		—		11,128		—
Equity securities (3)	1,597		1,597		—		—
Total	$	396,499	$	80,965	$	315,534	$	—

(1) Included in cash and cash equivalents on our condensed consolidated balance sheet.

(2) Included in short-term investments on our condensed consolidated balance sheet.

(3) Included in other current assets on our condensed consolidated balance sheet.