Fair Value Measurements

9 Months Ended

Sep. 30, 2013

Fair Value Disclosures [Abstract]

Fair Value Measurements

3. Fair Value Measurements

We measure our cash equivalents and short-term investments at fair value. Fair value is an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or a liability. A three-tier fair value hierarchy is established as a basis for considering such assumptions and for inputs used in the valuation methodologies in measuring fair value:

Level 1:	Quoted prices in active markets for identical assets or liabilities.
Level 2:	Directly or indirectly observable market-based inputs or unobservable inputs used in models or other valuation methodologies.
Level 3:	Unobservable inputs that are not corroborated by market data. The inputs require significant management judgment or estimation.

We classify our cash equivalents and short-term investments within Level 1 or Level 2 because our cash equivalents and short-term investments are valued using quoted market prices or alternative pricing sources and models utilizing market observable inputs.

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

	Quoted Prices in Active Markets for Identical Assets (Level 1)		Direct or Indirect Observable Inputs (Level 2)		Total
Assets:
Cash equivalents—money market fund	$	9,939	$	—	$	9,939
Short-term investments:
Corporate commercial paper		—		1,250		1,250
Foreign government bonds		—		1,001		1,001
Corporate debt securities		—		5,802		5,802
Total short-term investments		—		8,053		8,053
Restricted cash—money market fund		250		—		250
Total assets measured at fair value	$	10,189	$	8,053	$	18,242

 

	Quoted Prices in Active Markets for Identical Assets (Level 1)		Direct or Indirect Observable Inputs (Level 2)		Total
Assets:
Cash equivalents—money market fund	$	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