Short-term Investments (Tables)

6 Months Ended

12 Months Ended

Jun. 30, 2013

Dec. 31, 2012

Marketable Securities Measured at Fair Value

As of December 31, 2012, the Company’s short-term investments were $25.1 million, consisting of certificates of deposit of $1.0 million and marketable securities measured at fair value as follows (in thousands):

	December 31, 2012
	Amortized cost		Unrealized gains		Unrealized loss			Fair value
	(unaudited)
U.S. Agency notes	$	3,856	$	1	$	—		$	3,857
Corporate bonds		11,128		1		(3	)		11,126
Commercial paper		9,142		—		—			9,142
Total Marketable Securities	$	24,126	$	2	$	(3	)	$	24,125

As of June 30, 2013, the Company’s short-term investments were $61.6 million, consisting of certificates of deposit of $1.0 million and marketable securities measured at fair value as follows (in thousands):

	June 30, 2013
	Amortized cost		Unrealized gains		Unrealized loss			Fair value
	(unaudited)
U.S. Agency notes	$	20,530	$	1	$	(6	)	$	20,525
Corporate bonds		28,554		2		(28	)		28,528
Commercial paper		11,518		—		—			11,518
Total Marketable Securities	$	60,602	$	3	$	(34	)	$	60,571

As of December 31, 2011, the Company’s short-term investments were $20.4 million, consisting of certificates of deposit of $1.6 million and marketable securities measured at fair value as follows (in thousands):

	December 31, 2011
	Amortized Cost		Unrealized Gains		Unrealized Loss			Fair Value
U.S. Treasury Notes	$	403	$	—	$	—		$	403
U.S. Agency Notes		3,441		—		—			3,441
Corporate bonds		10,210		1		(12	)		10,199
Commercial paper		4,693		1		(1	)		4,693
Total Marketable Securities	$	18,747	$	2	$	(13	)	$	18,736

As of December 31, 2012, the Company’s short-term investments were $25.1 million, consisting of certificates of deposit of $1.0 million and marketable securities measured at fair value as follows (in thousands):

	December 31, 2012
	Amortized Cost		Unrealized Gains		Unrealized Loss			Fair Value
U.S. Treasury Notes	$	3,856	$	1	$	—		$	3,857
U.S. Agency Notes		11,128		1		(3	)		11,126
Corporate bonds		9,142		—		—			9,142
Total Marketable Securities	$	24,126	$	2	$	(3	)	$	24,125