Fair Value Measurements

9 Months Ended

Sep. 30, 2017

Fair Value Disclosures [Abstract]

Fair Value Measurements

4. 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 measured at fair value on a recurring basis as of September 30, 2017 and December 31, 2016 are summarized below (in thousands):

	September 30, 2017
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Direct or Indirect Observable Inputs (Level 2)		Total
Assets
Cash equivalents:
Money market funds	$	447	$	—	$	447
Corporate commercial paper		—		2,999		2,999
Corporate debt securities		—		3,752		3,752
Total cash equivalents		447		6,751		7,198
Short-term investments:
Corporate commercial paper		—		7,174		7,174
Corporate debt securities		—		6,453		6,453
Total short-term investments		—		13,627		13,627
Total assets measured at fair value	$	447	$	20,378	$	20,825

	December 31, 2016
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Direct or Indirect Observable Inputs (Level 2)		Total
Assets
Cash equivalents:
Money market funds	$	2,796	$	—	$	2,796
Corporate commercial paper		—		500		500
Total cash equivalents		2,796		500		3,296
Short-term investments:
Corporate commercial paper		—		11,465		11,465
Corporate debt securities		—		7,423		7,423
Total short-term investments		—		18,888		18,888
Total assets measured at fair value	$	2,796	$	19,388	$	22,184

As of September 30, 2017 and December 31, 2016, contractual maturities of our short-term investments were less than one year, and gross unrealized gains and losses on those investments were not material.