Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2011

Fair Value Measurements [Abstract]

Valuation of the company's assets measured at fair value

	Level 1		Level 2			Level 3		Total
	(In thousands)
As of December 31, 2011
Money market funds	$	111,256	$	—		$	—	$	111,256
Securities available-for-sale
U.S. government obligations		—		55,460			—		55,460
Municipal securities		—		20,612			—		20,612
Corporate bonds		—		2,038			—		2,038
Foreign currency forward contract		—		155			—		155
	$	111,256	$	78,265		$	—	$	189,521
As of December 31, 2010
Money market funds	$	96,661	$	—		$	—	$	96,661
Securities available-for-sale
U.S. government obligations		—		41,351			—		41,351
Municipal securities		—		29,145			—		29,145
Corporate bonds		—		2,056			—		2,056
Foreign currency forward contract		—		(337	)		—		(337	)
	$	96,661	$	72,215		$	—	$	168,876

Summary of the foreign currency forward contract

	As of December 31,
	2011		2010
	(In thousands)
Notional value	$	28,671	$	29,117
Fair value of notional		28,516		29,454
Gross and net fair value asset (liability)	$	155	$	(337	)

Summary of the company's securities available-for-sale

	Amortized cost		Gross unrealized gains		Gross unrealized losses			Estimated fair value
			(In thousands)
As of December 31, 2011
U.S. government obligations	$	53,832	$	1,628	$	—		$	55,460
Municipal securities		20,613		7		(8	)		20,612
Corporate bonds		2,028		10		—			2,038
Total securities available-for-sale	$	76,473	$	1,645	$	(8	)	$	78,110
As of December 31, 2010
U.S. government obligations	$	40,383	$	968	$	—		$	41,351
Municipal securities		29,150		14		(19	)		29,145
Corporate bonds		2,056		—		—			2,056
Total securities available-for-sale	$	71,589	$	982	$	(19	)	$	72,552

Summary of contractual maturities of securities available-for-sale

	As of December 31,
	2011		2010
	(In thousands)
Less than one year	$	31,554	$	23,593
Due in 1 — 5 years		46,556		48,959
Total securities available-for-sale	$	78,110	$	72,552

Fair values and unrealized losses on securities available-for-sale

	Less than Twelve Months					Twelve Months or More				Total
	Estimated fair value		Gross unrealized losses			Estimated fair value		Gross unrealized losses		Estimated fair value		Gross unrealized losses
						(In thousands)
As of December 31, 2011
U.S. government obligations	$	—	$	—		$	—	$	—	$	—	$	—
Municipal securities		9,529		(8	)		—		—		9,529		(8	)
Corporate bonds		—		—			—		—		—		—
Total	$	9,529	$	(8	)	$	—	$	—	$	9,529	$	(8	)
As of December 31, 2010
U.S. government obligations	$	—	$	—		$	—	$	—	$	—	$	—
Municipal securities		18,218		(19	)		—		—		18,218		(19	)
Corporate bonds		—		—			—		—		—		—
Total	$	18,218	$	(19	)	$	—	$	—	$	18,218	$	(19	)