Fair Value Measurements

6 Months Ended

Jun. 30, 2014

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 June 30, 2014 and December 31, 2013 are summarized below (in thousands):

	June 30, 2014
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Direct or Indirect Observable Inputs (Level 2)		Total
Assets
Cash equivalents:
Money market funds	$	7,306	$	—	$	7,306
Corporate debt		—		1,252		1,252
Total cash equivalents		7,306		1,252		8,558
Short-term investments:
Corporate commercial paper		—		1,198		1,198
Corporate debt		—		11,831		11,831
Total short-term investments		—		13,029		13,029
Restricted cash—money market fund		250		—		250
Total assets measured at fair value	$	7,556	$	14,281	$	21,837

	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 funds	$	8,989	$	—	$	8,989
Corporate debt		—		2,000		2,000
Total cash equivalents		8,989		2,000		10,989
Short-term investments:
Corporate commercial paper		—		1,500		1,500
Foreign government bonds		—		1,001		1,001
Corporate debt		—		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	$	9,239	$	9,295	$	18,534