Cash, cash equivalents and marketable securities

9 Months Ended

Sep. 30, 2012

Cash, cash equivalents and marketable securities

3. Cash, cash equivalents and marketable securities

The following is a summary of cash, cash equivalents and available-for-sale marketable securities as of September 30, 2012 and December 31, 2011 (in thousands):

	Amortized Cost		Unrealized Gains		Unrealized Losses			Estimated Fair Value
September 30, 2012:
Cash and cash equivalents:
Cash	$	2,665	$	—	$	—		$	2,665
Money market funds		18,862		—		—			18,862
U.S. government agency securities		870		—		—			870
Corporate debt securities		2,253		—		—			2,253
Total cash and cash equivalents		24,650		—		—			24,650
Marketable securities available-for-sale:
U.S. government agency securities		101,274		34		(4	)		101,304
Corporate debt securities		22,326		—		(1	)		22,325
Total marketable securities available-for-sale		123,600		34		(5	)		123,629
Total cash, cash equivalents and marketable securities	$	148,250	$	34	$	(5	)	$	148,279
December 31, 2011:
Cash and cash equivalents:
Cash	$	2,290	$	—	$	—		$	2,290
Money market funds		17,171		—		—			17,171
U.S. government agency securities		9,438		—		—			9,438
Corporate debt securities		3,044		—		(2	)		3,042
Total cash and cash equivalents		31,943		—		(2	)		31,941
Marketable securities available-for-sale:
U.S. Government agency securities		26,488		—		(6	)		26,482
Corporate debt securities		55,533		9		(4	)		55,538
Total marketable securities available-for-sale		82,021		9		(10	)		82,020
Total cash, cash equivalents and marketable securities	$	113,964	$	9	$	(12	)	$	113,961

The following is a summary of the amortized cost and estimated fair value of available-for-sale securities at September 30, 2012, by contractual maturity (in thousands):

	September 30, 2012
	Amortized Cost		Estimated Fair Value
Mature in one year or less	$	76,342	$	76,360
Mature after one year through two years		47,258		47,269
	$	123,600	$	123,629

There were no realized gains or losses from the sale of marketable securities in the three and nine months ended September 30, 2012 and 2011. All of our investments are classified as short-term and available-for-sale, as we may not hold our investments until maturity. The corporate debt securities held as of September 30, 2012 and December 31, 2011, were secured by the Federal Deposit Insurance Corporation through the Temporary Liquidity Guarantee Program.