Organization and Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2017

Basic weighted average common shares outstanding, and the potentially dilutive securities excluded from loss per share computations because they are antidilutive, are as follows for the years ended December 31, 2017 and 2016:

	2017		2016
Basic and diluted weighted average common stock shares outstanding		13,263,881		12,642,996
Potentially dilutive securities excluded from loss per share computations:
Common stock options		3,390,009		2,513,861
Common stock purchase warrants		6,688,849		7,603,141
Unvested Restricted Stock		237,926		98,439

Schedule of weighted-average assumptions

The fair value of options at the date of grant is determined under the Black-Scholes option pricing model. During the years ended December 31, 2017 and 2016, the following weighted-average assumptions were used:

Assumptions	2017			2016
Risk-free rate		2.12	%		1.51	%
Annual rate of dividends		––			––
Historical volatility		74	%		75	%
Expected life		5.7 years			7.0 years