Fair Value Measurements

12 Months Ended

Dec. 31, 2011

Fair Value Measurements

Fair Value Measurements

Note 3.    Fair Value Measurements

        The Company measures certain financial assets, including cash equivalents and marketable securities, at their fair value on a recurring basis. The fair value of these financial assets was determined based on a hierarchy of three levels of inputs, of which the first two are considered observable and the last unobservable, as follows:

        Level 1:    Quoted prices in active markets for identical assets or liabilities.

        Level 2:    Observable inputs other than Level 1 inputs, such as quoted prices for similar assets or liabilities, quoted prices in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.

        Level 3:    Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities.

        Assets and liabilities measured at fair value are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. The Company's assessment of the significance of a particular input to the fair value measurement in its entirety requires management to make judgments and consider factors specific to the asset or liability. The Company did not have any non-financial assets or liabilities that were measured or disclosed at fair value on a recurring basis at December 31, 2011 and 2010, respectively. The following tables set forth the Company's financial instruments that were measured at fair value on a recurring basis at December 31, 2011 and 2010 by level within the fair value hierarchy:

	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 agencies		—		19,350		—		19,350
Commercial paper		—		19,999		—		19,999
Corporate debt securities		—		29,005		—		29,005
Total	$	7,377	$	68,354	$	—	$	75,731

	Actively Quoted Markets for Identical Assets Level 1		Significant Other Observable Inputs Level 2		Significant Unobservable Inputs Level 3		Balance at December 31, 2010
	(In thousands)
As of December 31, 2010:
Assets
Money market deposits	$	9,956	$	—	$	—	$	9,956
U.S. Treasury securities		3,818		—		—		3,818
Debt securities of U.S. government-sponsored agencies		—		20,819		—		20,819
Commercial paper		—		11,869		—		11,869
Corporate debt securities		—		9,129		—		9,129
Total	$	13,774	$	41,817	$	—	$	55,591

        The Company's debt securities of U.S. government-sponsored entities, commercial paper and corporate bonds are classified as Level 2 as they are valued using multi-dimensional relational pricing models that use observable market inputs, including benchmark yields, reported trades, broker-dealer quotes, issuer spreads, benchmark securities, bids, offers and reference data. Not all inputs listed are available for use in the evaluation process on any given day for each security evaluation. In addition, market indicators and industry and economic events are monitored and may serve as a trigger to acquire further corroborating market data. There were no transfers between Level 1 and Level 2 categories during the years ended December 31, 2011 and 2010, respectively.

        All of the Company's marketable securities are classified as available for sale. The following tables summarize the Company's available-for-sale marketable securities as of the dates indicated:

	December 31, 2011
	Amortized Cost		Unrealized Gains		Unrealized Losses			Estimated Fair Value
	(In thousands)
Debt securities of U.S. government-sponsored entities	$	19,350	$	2	$	(2	)	$	19,350
Commercial paper		19,232		17		—			19,249
Corporate debt securities		29,052		5		(52	)		29,005
Total	$	67,634	$	24	$	(54	)	$	67,604

	December 31, 2010
	Amortized Cost		Unrealized Gains		Unrealized Losses			Estimated Fair Value
	(In thousands)
U.S. Treasury securities	$	3,818	$	—	$	—		$	3,818
Debt securities of U.S. government-sponsored entities		20,825		1		(7	)		20,819
Commercial paper		11,868		2		(1	)		11,869
Corporate debt securities		9,134		—		(5	)		9,129
Total	$	45,645	$	3	$	(13	)	$	45,635

        The Company had no realized gains or losses on its available-for-sale marketable securities for the years ended December 31, 2011 and 2010, respectively.

        All of the Company's available-for-sale marketable securities had contractual maturities of one year or less as of December 31, 2011 and 2010, respectively.