Fair Value Measurements

12 Months Ended

Dec. 31, 2013

Fair Value Disclosures [Abstract]

Fair Value Measurements

3. Fair Value Measurements

We measure our cash equivalents, marketable securities and restricted cash 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, marketable securities and restricted cash within Level 1 or Level 2. This is because we value these items using quoted market prices or alternative pricing sources and models utilizing market observable inputs that are actively quoted and can be validated through external sources, including third-party pricing services, brokers and market transactions. We review the pricing techniques and methodologies of the independent pricing service for Level 2 investments and believe that the policies adequately consider market activity, either based on specific transactions for the security valued or based on modeling of securities with similar credit quality, duration, yield and structure that were recently traded.

Assets and liabilities measured at fair value on a recurring basis are summarized below (in thousands):

	December 31, 2013
	Quoted Prices in Active  Markets for Identical Assets (Level 1)		Direct or  Indirect Observable Inputs (Level 2)		Total
Assets:
Cash equivalents—money market fund	$	10,989	$	—	$	10,989
Short-term investments:
Corporate commercial paper		—		1,500		1,500
Foreign government bonds		—		1,001		1,001
Corporate debt securities		—		4,794		4,794
Total short-term investments		—		7,295		7,295
Restricted cash—money market fund		250		—		250
Total assets measured at fair value	$	11,239	$	7,295	$	18,534

	December 31, 2012
	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