Fair Value Measurements (Tables)

9 Months Ended

Sep. 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 September 30, 2012
	(In thousands)
As of September 30, 2012:
Assets
Money market deposits	$	6,731	$	—	$	—	$	6,731
U.S. Treasury securities	1,284		—		—		1,284
Debt securities of U.S. government-sponsored entities	—		767		—		767
Commercial paper	—		26,263		—		26,263
Corporate debt securities	—		40,708		—		40,708
Total	$	8,015	$	67,738	$	—	$	75,753

	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

	September 30, 2012
	Amortized Cost		Unrealized Gains		Unrealized Losses			Estimated Fair Value
	(In thousands)
U.S. Treasury securities	$	1,283	$	1	$	—		$	1,284
Debt securities of U.S. government-sponsored entities	767		—		—			767
Commercial paper	26,244		19		—			26,263
Corporate debt securities	40,712		7		(11		)	40,708
Total	$	69,006	$	27	$	(11	)	$	69,022

	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

	September 30, 2012				December 31, 2011
	Amortized  Cost		Estimated Fair Value		Amortized  Cost		Estimated Fair Value
	(In thousands)
Due in one year or less	$	68,236	$	68,251	$	67,635	$	67,605
Due in more than one year but less than five years	770		771		—		—
Total	$	69,006	$	69,022	$	67,635	$	67,605