Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2013

Fair Value Measurements [Abstract]

Assets and liabilities measured at fair value on a recurring basis

Assets and liabilities measured at fair value on a recurring basis as of June 30, 2013 and December 31, 2012 are summarized below (in thousands):

	June 30, 2013
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Direct or Indirect Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
Assets
Cash equivalents:
Money market funds	$	8,777	$	—	$	—	$	8,777
Total cash equivalents		8,777		—		—		8,777
Short-term investments:
Corporate commercial paper		—		1,250		—		1,250
Foreign government bonds		—		1,001		—		1,001
Corporate debt securities		—		7,080		—		7,080
Total short-term investments		—		9,331		—		9,331
Restricted cash—money market fund		875		—		—		875
Total assets measured at fair value	$	9,652	$	9,331	$	—	$	18,983

	December 31, 2012
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Direct or Indirect Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
Assets
Cash equivalents:
Money market funds	$	7,313	$	—	$	—	$	7,313
Total cash equivalents		7,313		—		—		7,313
Short-term investments:
Municipal securities		—		356		—		356
Corporate commercial paper		—		4,374		—		4,374
Foreign government bonds		—		999		—		999
Corporate debt securities		—		4,097		—		4,097
Total short-term investments		—		9,826		—		9,826
Restricted cash—money market fund		875		—		—		875
Total assets measured at fair value	$	8,188	$	9,826	$	—	$	18,014