Fair Value (Tables)

3 Months Ended

Mar. 31, 2013

Fair Value Disclosures [Abstract]

Financial assets and liabilities measured at fair value on a recurring basis

Financial assets (excluding cash balances) measured at fair value on a recurring basis as of March 31, 2013 and December 31, 2012 are summarized as follows (in thousands):

	As of March 31, 2013								As of December 31, 2012
	Fair Value Measurement Using								Fair Value Measurement Using
	Level 1		Level 2		Level 3		Total		Level 1		Level 2		Level 3		Total
Assets:
Money market funds	$	23,276	$	—	$	—	$	23,276	$	17,815	$	—	$	—	$	17,815
Corporate bonds	—		1,002		—		1,002		—		3,313		—		3,313
Total cash equivalents	23,276		1,002		—		24,278		17,815		3,313		—		21,128
Commercial paper and corporate bonds	—		45,281		—		45,281		—		63,675		—		63,675
U.S. Treasury and U.S. government agency debt securities	—		41,460		—		41,460		—		26,196		—		26,196
Total marketable securities	—		86,741		—		86,741		—		89,871		—		89,871
Total financial assets	$	23,276	$	87,743	$	—	$	111,019	$	17,815	$	93,184	—		$	110,999
Liabilities:
Contingent consideration	$	—	$	—	$	861	$	861	$	—	$	—	$	801	$	801

Summary of changes in fair value of financial liabilities

The following table provides a summary of changes in fair value of the Company’s Level 3 financial liabilities during the first three months of 2013 (in thousands):

	Contingent Consideration
Balance at January 1, 2013 (included in other long-term liabilities)	$	801
Change in fair value	60
Balance at March 31, 2013 (included in accrued expenses and other)	$	861