Fair Value Measurements

12 Months Ended

Dec. 31, 2013

Fair Value Disclosures [Abstract]

Fair Value Measurements

3. Fair Value Measurements

The following tables present information about the Company’s financial liabilities measured at fair value on a recurring basis as of December 31, 2013 and 2012 and indicate the fair value hierarchy of the valuation techniques utilized by the Company to determine such fair value. The Company had no financial liabilities as of December 31, 2013. As a basis for categorizing inputs, the Company uses a three-tier fair value hierarchy, which prioritizes the inputs used to measure fair value from market based assumptions to entity specific assumptions:

Level 1: Observable inputs such as quoted prices in active markets;

Level 2: Inputs, other than the quoted prices in active markets, that are observable either directly or indirectly; and

Level 3: Unobservable inputs in which there is little or no market data, which require the reporting entity to develop its own assumptions.

The Company’s Level 3 financial liabilities consisted of warrant liabilities related to warrants to purchase preferred stock. All warrants were measured at fair value utilizing the Black-Scholes option pricing model.

The fair value of the outstanding preferred stock warrants at December 31, 2012 was estimated using the Black-Scholes option pricing model with the following assumptions:

	December 31, 2012
Assumed risk-free-interest rate		0.25% — 1.78%
Assumed volatility		80%
Expected warrant life		2.08 — 9.50 years
Expected dividend yield		0.0%

Liabilities measured at fair value on a recurring basis as of December 31, 2012 are as follows:

			Fair Value Measurements at Reporting Date Using
	Balance as of December 31, 2012		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Liabilities:
Preferred stock warrant liability	$	56,000	$	—	$	—	$	56,000
Total liabilities		56,000	$	—	$	—	$	56,000

The following table is a reconciliation of all the Company’s liabilities measured using significant unobservable inputs (Level 3) for the years ended December 31, 2013 and 2012:

	Warrant Liability
Fair value measurement at December 31, 2011	$	39,000
Warrants issued in connection with loan and security agreement		24,250
Change in fair value of warrant liability		(7,250	)
Fair value measurement at December 31, 2012		56,000
Warrants issues in connection with loan and security agreement		49,000
Change in fair value of warrant liability		82,000
Reclassification to additional paid-in capital at initial public offering		(187,000	)
Fair value measurement at December 31, 2013	$	—