Fair Value Measurements

6 Months Ended

Jun. 30, 2015

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, 2015 and December 31, 2014 are summarized below (in thousands):

	June 30, 2015
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Direct or Indirect Observable Inputs (Level 2)		Total
Assets
Cash equivalents:
Money market funds	$	9,674	$	—	$	9,674
Corporate debt securities		—		250		250
Total cash equivalents		9,674		250		9,924
Short-term investments:
Corporate commercial paper		—		1,399		1,399
Corporate debt securities		—		16,065		16,065
Total short-term investments		—		17,464		17,464
Restricted cash—money market fund		250		—		250
Total assets measured at fair value	$	9,924	$	17,714	$	27,638

	December 31, 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	$	9,362	$	—	$	9,362
Corporate debt securities		—		1,002		1,002
Total cash equivalents		9,362		1,002		10,364
Short-term investments:
Corporate commercial paper		—		550		550
Corporate debt securities		—		12,713		12,713
Total short-term investments		—		13,263		13,263
Restricted cash—money market fund		250		—		250
Total assets measured at fair value	$	9,612	$	14,265	$	23,877