Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2013

Fair Value Disclosures [Abstract]

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

The following table summarizes the cash equivalents and marketable securities measured at fair value on a recurring basis as of June 30, 2013 (in thousands):

	Level 1		Level 2		Level 3		Total
Cash equivalents	$	76,459	$	—	$	—	$	76,459
Marketable securities:
Certificates of deposit		—		5,196		—		5,196
U.S. Treasuries		16,598		—		—		16,598
	$	93,057	$	5,196	$	—	$	98,253

The following table summarizes the cash equivalents and marketable securities measured at fair value on a recurring basis as of December 31, 2012 (in thousands):

	Level 1		Level 2		Level 3		Total
Cash equivalents	$	89,062	$	—	$	—	$	89,062
Marketable securities:
Certificates of deposit		—		7,384		—		7,384
U.S. Treasuries		29,295		—		—		29,295
	$	118,357	$	7,384	$	—	$	125,741