Fair Value Measurements

3 Months Ended

Mar. 31, 2019

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 March 31, 2019 and December 31, 2018 are summarized below (in thousands):

	March 31, 2019						December 31, 2018
	Quoted Prices in Active Markets for Identical Assets (Level 1)		Direct or Indirect Observable Inputs (Level 2)		Total		Quoted Prices in Active Markets for Identical Assets (Level 1)		Direct or Indirect Observable Inputs (Level 2)		Total
Assets
Cash equivalents:
Money market funds	$	264	$	—	$	264	$	1,277	$	—	$	1,277
Government and agencies		—		500	$	500		—		—		—
Corporate commercial paper		—		749		749		—		1,198		1,198
Corporate debt		—		—		—		—		750		750
Total cash equivalents		264		1,249		1,513		1,277		1,948		3,225
Restricted cash:
Money market funds		601		—		601		526		—		526
Short-term investments:
Corporate commercial paper		—		5,276		5,276		—		3,874		3,874
Corporate debt		—		1,897		1,897		—		2,535		2,535
Total short-term investments		—		7,173		7,173		—		6,409		6,409
Total assets measured at fair value	$	865	$	8,422	$	9,287	$	1,803	$	8,357	$	10,160

As of March 31, 2019 and December 31, 2018, contractual maturities of our short-term investments were less than one year, and gross unrealized gains and losses on those investments were not material.