Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2012

Fair Value Measurements

Schedule of financial instruments measured at fair value on recurring basis

	Actively Quoted Markets for Identical Assets  Level 1		Significant Other Observable Inputs Level 2		Significant Unobservable Inputs Level 3		Balance at June 30, 2012
	(In thousands)
As of June 30, 2012:
Assets
Money market deposits	$	10,160	$	—	$	—	$	10,160
U.S. Treasury securities	1,291		—		—		1,291
Debt securities of U.S. government-sponsored entities	—		773		—		773
Commercial paper	—		23,743		—		23,743
Corporate debt securities	—		39,803		—		39,803
Total	$	11,451	$	64,319	$	—	$	75,770

	Actively Quoted Markets for Identical Assets Level 1		Significant Other Observable Inputs Level 2		Significant Unobservable Inputs Level 3		Balance at December 31, 2011
	(In thousands)
As of December 31, 2011:
Assets
Money market deposits	$	7,377	$	—	$	—	$	7,377
Debt securities of U.S. government-sponsored entities	—		19,350		—		19,350
Commercial paper	—		19,999		—		19,999
Corporate debt securities	—		29,005		—		29,005
Total	$	7,377	$	68,354	$	—	$	75,731

Schedule of available-for-sale marketable securities

	June 30, 2012
	Amortized Cost		Unrealized Gains		Unrealized Losses			Estimated Fair Value
	(In thousands)
U.S. Treasury securities	$	1,290	$	1	$	—		$	1,291
Debt securities of U.S. government-sponsored entities	773		—		—			773
Commercial paper	17,974		20		—			17,994
Corporate debt securities	36,826		6		(29		)	36,803
Total	$	56,863	$	27	$	(29	)	$	56,861

	December 31, 2011
	Amortized  Cost		Unrealized  Gains		Unrealized  Losses			Estimated  Fair Value
	(In thousands)
Debt securities of U.S. government-sponsored entities	$	19,351	$	2	$	(2	)	$	19,351
Commercial paper	19,232		17		—			19,249
Corporate debt securities	29,052		5		(52		)	29,005
Total	$	67,635	$	24	$	(54	)	$	67,605

Schedule of available-for-sale marketable securities by contractual maturity

	June 30, 2012				December 31, 2011
	Amortized  Cost		Estimated Fair Value		Amortized  Cost		Estimated Fair Value
	(In thousands)
Due in one year or less	$	55,573	$	55,570	$	67,635	$	67,605
Due in more than one year but less than five years	1,290		1,291		—		—
Total	$	56,863	$	56,861	$	67,635	$	67,605