Marketable Securities

9 Months Ended

Sep. 30, 2012

Marketable Securities [Abstract]

Marketable securities

4. Marketable securities

We invest our excess cash primarily in U.S. government agency and treasury notes, money market funds and municipal notes and bonds that mature within one year.

All cash equivalents and marketable securities are classified as available-for-sale and are summarized as follows:

	September 30, 2012
	Fair value		Amortized cost		Gross unrealized gains		Gross unrealized losses
	(in thousands)
Money market funds	$	57,918	$	57,918	$	—	$	—
U.S. government bonds and notes		22,052		22,051		1		—
Total cash equivalents and marketable securities		79,970		79,969		1		—
Cash		39,817		39,817		—		—
Total cash, cash equivalents and marketable securities	$	119,787	$	119,786	$	1	$	—

Available-for-sale securities are reported at fair value on the condensed consolidated balance sheet and classified as follows:

	September 30, 2012		December 31, 2011
	(in thousands)
Cash equivalents	$	57,918	$	2,062
Short term marketable securities		22,052		—
Total cash equivalents and marketable securities		79,970		2,062
Cash		39,817		13,921
Total cash, cash equivalents and marketable securities	$	119,787	$	15,983

We invest in high quality, highly liquid debt securities that mature within one year. We hold all of our marketable securities as available-for-sale and mark them to market. We currently do not intend to sell these investments nor are we required to sell these investments. As of September 30, 2012, marketable debt securities with a fair value of $80.0 million, which mature within one year had insignificant unrealized losses. However, we cannot provide any assurance that our portfolio of cash, cash equivalents and marketable securities will not be impacted by adverse conditions in the financial markets, which may require us in the future to record an impairment charge for credit losses which could adversely impact our financial results.

The estimated fair value of cash equivalents and marketable securities as of September 30, 2012 was $80 million. The unrealized gains, net, were insignificant in relation to our total available-for-sale portfolio. The unrealized gains, net, were primarily due to market conditions and the demand for and duration of our U.S. government bonds and notes.