Warrants - (Tables)

12 Months Ended

Dec. 31, 2017

Class of Warrant or Right [Line Items]

Warrants activity is summarized as follows:



	Shares(1)		Weighted Average Exercise Price		Range of Exercise Prices
Outstanding at December 31, 2015	913,434		$	3.54	$6.25 - $52.00
Issued	489,475		$	2.20	$2.20
Exercised	(410,824	)	$	1.73	$0.05 - $3.00
Expired	(12,216	)	$	22.50	$22.50
Outstanding at December 31, 2016	979,869		$	6.36	$2.20 - $21.00
Issued	—		$	—	$-
Exercised	(75,399	)	$	19.46	$13.25-$21.00
Expired	—		$	—	$-
Outstanding at December 31, 2017	904,470		$	5.27	$2.20 - $21.00
Exercisable at December 31, 2017	904,470		$	5.27	$2.20 - $21.00

_______________________________________________________________________________


(1)	Outstanding and exercisable information includes 21,920 equity-classified warrants as of December 31, 2017.

Black Scholes

Class of Warrant or Right [Line Items]

Schedule of of Ranges of Warrant Valuation Assumptions

The assumptions used in the Black-Scholes option-pricing model to estimate the fair value of the warrant liability were as follows:



	December 31,
	2017	2016
Expected volatility	91.0 - 104.5	97.7% - 106.4%
Risk-free interest rate	1.86% - 2.09%	1.40% - 1.92%
Dividend yield	—	—
Expected life in years	1.8 - 4.0	2.8 - 5.0

Monte Carlo Simulation Model

Class of Warrant or Right [Line Items]

Schedule of of Ranges of Warrant Valuation Assumptions

The assumptions used in the Monte Carlo simulation model to estimate the fair value of the warrant liability were as follows:



	December 31,
	2017	2016
Expected volatility	91.3 - 95.7	97.7%-106.4%
Risk-free interest rate	1.53% - 1.87%	1.03%-1.43%
Dividend yield	—	—
Expected life in years	0.5- 1.9	1.5-2.9

- Definition

Tabular disclosure of warrants or rights issued. Warrants and rights outstanding are derivative securities that give the holder the right to purchase securities (usually equity) from the issuer at a specific price within a certain time frame. Warrants are often included in a new debt issue to entice investors by a higher return potential. The main difference between warrants and call options is that warrants are issued and guaranteed by the company, whereas options are exchange instruments and are not issued by the company. Also, the lifetime of a warrant is often measured in years, while the lifetime of a typical option is measured in months. Disclose the title of issue of securities called for by warrants and rights outstanding, the aggregate amount of securities called for by warrants and rights outstanding, the date from which the warrants or rights are exercisable, and the price at which the warrant or right is exercisable.

+ References + Details