Fair Value (Tables)

9 Months Ended

Sep. 30, 2011

Fair Value [Abstract]

Financial assets measured at fair value on a recurring basis

	Level 1		Level 2		Level 3		Total
	(In thousands)
September 30, 2011
Cash equivalents:
Money market funds	$	45,256	$	—	$	—	$	45,256
Short-term investments:
State, municipal and local government agencies bonds		—		34,167		—		34,167
Corporate bonds		—		18,297		—		18,297
U.S. federal government bonds		—		8,586		—		8,586
Commercial paper		—		4,598		—		4,598
Total	$	45,256	$	65,648	$	—	$	110,904
December 31, 2010
Cash equivalents:
Money market funds	$	68,395	$	—	$	—	$	68,395
Short-term investments:
State, municipal and local government agencies bonds		—		11,931		—		11,931
Corporate bonds		—		11,907		—		11,907
Total	$	68,395	$	23,838	$	—	$	92,233

Maturities of short-term investments

	September 30, 2011		December 31, 2010
	(In thousands)
Short-term investments:
Less than one year	$	37,888	$	21,174
Due in 1 - 2 years		11,555		2,664
Due in 3 - 30 years (1)		16,205		—
Total short-term investments	$	65,648	$	23,838

(1) Represents the final maturity of variable rate demand notes. These securities have a put right on the part of the Company which allows the Company to put the security to the issuer, generally within a month of the balance sheet date. Should the Company exercise its put option on the put date, it is entitled to receive the par value of the security plus any accrued interest.

Summary of available-for-sale securities

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
	(In thousands)
September 30, 2011
State, municipal and local government agencies bonds	$	34,135	$	37	$	(5	)	$	34,167
Corporate bonds		18,321		—		(24	)		18,297
U.S. federal government bonds		8,584		3		(1	)		8,586
Commercial paper		4,598		—		—			4,598
Total	$	65,638	$	40	$	(30	)	$	65,648
December 31, 2010
State, municipal and local government agencies bonds	$	11,915	$	20	$	(4	)	$	11,931
Corporate bonds		11,894		20		(7	)		11,907
Total	$	23,809	$	40	$	(11	)	$	23,838