Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2012

Fair Value Measurements [Abstract]

Valuation of company's assets and liabilities measured at fair value

	Level 1		Level 2		Level 3		Total
	(In thousands)
As of December 31, 2012
Money market funds	$	83,519	$	—	$	—	$	83,519
Securities available-for-sale
U.S. government obligations		—		31,104		—		31,104
Municipal securities		—		17,947		—		17,947
Corporate bonds		—		2,157		—		2,157
Foreign currency forward and option contracts		—		15		—		15
	$	83,519	$	51,223	$	—	$	134,742
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

Summary of foreign currency forward contract

	As of December 31,
	2012			2011
	(In thousands)
Notional value	$	15,792		$	28,671
Fair value of notional		15,809			28,516
Gross and net fair value (liability) asset	$	(17	)	$	155

Summary of company's securities available-for-sale

			Gross		Gross			Estimated
	Amortized		unrealized		unrealized			fair
	cost		gains		losses			value
	(In thousands)
As of December 31, 2012
U.S. government obligations	$	30,255	$	849	$	—		$	31,104
Municipal securities		17,941		10		(4	)		17,947
Corporate bonds		2,159		—		(2	)		2,157
Total securities available-for-sale	$	50,355	$	859	$	(6	)	$	51,208
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

Summary of contractual maturities of securities available-for-sale

	As of December 31,
	2012		2011
	(In thousands)
Less than one year	$	10,870	$	31,554
Due in 1—5 years		40,338		46,556
Total securities available-for-sale	$	51,208	$	78,110

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

	Less than Twelve Months					Twelve Months or More				Total
	Estimated		Gross			Estimated		Gross		Estimated		Gross
	fair		unrealized			fair		unrealized		fair		unrealized
	value		losses			value		losses		value		losses
						(In thousands)
As of December 31, 2012
U.S. government obligations	$	—	$	—		$	—	$	—	$	—	$	—
Municipal securities		2,780		(4	)		—		—		2,780		(4	)
Corporate bonds		2,157		(2	)		—		—		2,157		(2	)
Total	$	4,937	$	(6	)	$	—	$	—	$	4,937	$	(6	)
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	)