Cash and Cash Equivalents and Marketable Securities (Tables)

9 Months Ended

Sep. 30, 2013

Cash and Cash Equivalents and Marketable Securities [Abstract]

Unrealized gains and losses related to marketable investments and long-term investments

The following tables summarize unrealized gains and losses related to our marketable investments, designated as available-for-sale (in thousands):

September 30, 2013	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Market Value
Cash and cash equivalents:
Cash	$	1,830	$	—	$	—		$	1,830
Money market funds		12,180		—		—			12,180
Commercial paper		1,150		—		—			1,150
Total cash and cash equivalents		15,160		—		—			15,160
Marketable securities:
U.S. government notes		5,997		14		—			6,011
U.S. government agencies		30,499		40		(13	)		30,526
Municipal securities		2,604		2		(4	)		2,602
Commercial paper		9,357		4		—			9,361
Corporate debt securities		18,570		56		(5	)		18,621
Total marketable investments		67,027		116		(22	)		67,121
Total cash, cash equivalents and marketable investments	$	82,187	$	116	$	(22	)	$	82,281

December 31, 2012	Amortized Cost		Gross Unrealized Gains		Gross Unrealized  Losses			Fair Market Value
Cash and cash equivalents:
Cash	$	2,198	$	—	$	—		$	2,198
Money market funds		17,348		—		—			17,348
Commercial paper		4,000		—		—			4,000
Total cash and cash equivalents		23,546		—		—			23,546
Marketable securities:
U.S. government notes		4,005		4		—			4,009
U.S. government agencies		24,910		48		—			24,958
Municipal securities		4,184		23		(1	)		4,206
Commercial paper		10,515		4		—			10,519
Corporate debt securities		18,281		59		(6	)		18,334
Total marketable investments		61,895		138		(7	)		62,026
Total cash, cash equivalents and marketable investments	$	85,441	$	138	$	(7	)	$	85,572

Estimated fair value of marketable investments and long-term investments classified by contractual maturity date

The following table summarizes the estimated fair value of our securities available-for-sale and classified as cash and cash equivalents and marketable investments classified by the contractual maturity date of the security as of September 30, 2013 (in thousands):

	Amount
Due in less than one year	$	31,472
Due in 1 to 3 years		36,799
	$	68,271