Cash Equivalents and Marketable Securities

12 Months Ended

Dec. 31, 2011

Cash Equivalents and Marketable Securities

Cash Equivalents and Marketable Securities

Note 2—Cash Equivalents and Marketable Securities

        At December 31, 2011 and 2010, cash and cash equivalents, short-term and long-term marketable securities primarily consisted of money market mutual funds, US government and US Government Sponsored Entities (GSE's), foreign government debt securities and high credit quality corporate debt securities. The Company's short-term and long-term marketable securities are classified as available-for-sale, with long-term marketable securities having a maturity date greater than one year from the end of the period.

        Marketable securities are summarized as follows (in thousands):

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses Less than 12 Months			Gross Unrealized Losses 12 Months or Longer		Aggregate Fair Value
Balance at December 31, 2011
Corporate debt securities	$	52,606	$	10	$	(11	)	$	—	$	52,605
US government debt securities		11,318		5		—			—		11,323
Foreign government debt securities		6,914		—		(17	)		—		6,897
Total	$	70,838	$	15	$	(28	)	$	—	$	70,825

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses Less than 12 Months			Gross Unrealized Losses 12 Months or Longer		Aggregate Fair Value
Balance at December 31, 2010
Corporate debt securities	$	22,597	$	6	$	(3	)	$	—	$	22,600
US government debt securities		47,466		12		(3	)		—		47,475
Total	$	70,063	$	18	$	(6	)	$	—	$	70,075

        The following table summarizes the contractual maturities of marketable securities at December 31, 2011 (in thousands):

	Amortized Cost		Aggregate Fair Value
Matures in less than one year	$	69,921	$	69,908
Matures in one to three years		917		917
Total	$	70,838	$	70,825

        The following table summarizes marketable securities with unrealized losses by contractual maturity dates at December 31, 2011 (in thousands):

	Less than 12 months					Greater than 12 months				Total
	Fair Value		Gross Unrealized Losses			Fair Value		Net Unrealized Losses		Fair Value		Net Unrealized Losses
Corporate debt securities	$	30,811	$	(11	)	$	—	$	—	$	30,811	$	(11	)
Foreign government debt securities		6,914		(17	)						6,914		(17	)
Total	$	37,725	$	(28	)	$	—	$	—	$	37,725	$	(28	)

        The gross unrealized losses related to marketable securities are primarily due to a decrease in the fair value of debt securities as a result of an increase in interest rates during fiscal 2011. For fixed income securities that have unrealized losses as of December 31, 2011, the Company has determined that (i) it does not have the intent to sell any of these investments prior to maturity and (ii) it is not more likely than not that it will be required to sell any of these investments before recovery of the entire amortized cost basis. In addition, the Company has evaluated these fixed income securities and has determined that no credit losses exist, as a majority of the Company's portfolio is backed by the federal government. As of December 31, 2011, all securities in an unrealized loss position have been in an unrealized loss position for less than one year. The Company's management has determined that the unrealized losses on its fixed income securities as of December 31, 2011 were temporary in nature.

        The Company had no realized gains or losses related to the Company's marketable securities for the years ending December 31, 2011, 2010 and 2009.