Warrants (Tables)

9 Months Ended

Sep. 30, 2017

Equity [Abstract]

Summary of Assumptions using Black- Scholes Option Pricing Model to estimate fair value

The fair value of the 2016 Placement Warrants of $5.7 million and $2.7 million at September 30, 2017 and December 31, 2016, respectively, was estimated using the Black-Scholes option pricing model and the following weighted-average assumptions:

	September 30, 2017		December 31, 2016
2016 Placement Warrant:
Expected term (in years)		5.9		6.7
Expected volatility		63.0%		63.6%
Risk-free interest rate		2.0%		2.3%
Expected dividend yield		0.0%		0.0%

The fair value of the 2017 Placement Warrants of $7.1 million was estimated using the Black-Scholes option pricing model and the following weighted-average assumptions:

	September 30, 2017
2017 Placement Warrant:
Expected term (in years)		6.3
Expected volatility		63.8%
Risk-free interest rate		2.1%
Expected dividend yield		0.0%