Fair Value Measurements (Tables)

6 Months Ended

12 Months Ended

Jun. 30, 2013

Dec. 31, 2012

Cash and Cash Equivalents and Marketable Securities, Measured at Fair Value on Recurring Basis

The Company’s cash equivalents and marketable securities that are measured at fair value on a recurring basis are classified as follows (in thousands):

	December 31, 2012						June 30, 2013
	Level 1		Level 2		Level 3		Level 1		Level 2		Level 3
							(unaudited)
Cash and Cash Equivalents:
Money market funds	$	14,055	$	—	$	—	$	35,832	$	—	$	—
U.S. Agency notes		—		—		—		—		—		—
Corporate bonds		—		150		—		—		—		—
Commercial paper		—		1,400		—		—		1,300		—
Marketable Securities:
U.S. Agency notes		—		3,857		—		—		20,525		—
Corporate bonds		—		11,126		—		—		28,528		—
Commercial paper				9,142						11,518
	$	14,055	$	25,675	$	—	$	35,832	$	61,871	$	—

The Company’s cash equivalents and marketable securities that are measured at fair value on a recurring basis are classified as follows (in thousands):

	December 31, 2011						December 31, 2012
	Level 1		Level 2		Level 3		Level 1		Level 2		Level 3
Cash Equivalents:
Money market funds	$	19,107	$	—	$	—	$	14,055	$	—	$	—
U.S. Agency notes		—		125		—		—		—		—
Corporate bonds		—		505		—		—		150		—
Commercial paper		—		—		—		—		1,400		—
Marketable Securities:
U.S. Treasury notes		403		—		—		—		—		—
U.S. Agency notes		—		3,441		—		—		3,857		—
Corporate bonds		—		10,199		—		—		11,126		—
Commercial paper		—		4,693		—		—		9,142		—
	$	19,510	$	18,963	$	—	$	14,055	$	25,675	$	—