Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2018

Assumptions Used to Calculate Fair Value of Warrants

Significant inputs utilized in the valuation of the Letter Agreement Warrants were:

	December 31, 2018	December 31, 2017
Expected volatility	108.53% - 115.04%	90.00%
Risk-free interest rate	2.59% - 2.69%	2.40%

Warrant Liability [Member]

Assumptions Used to Calculate Fair Value of Warrants

Fair value of the Letter Agreement Warrants was calculated as of their issuance date using the methods described in Note 18 using the following assumptions:

	December 5, 2017		July 30, 2018		December 11, 2018
Expected volatility	90.0%		95.29%		104.46%
Expected life of option, in years		7.0		7.0		7.0
Risk-free interest rate	2.8%		2.94%		2.77%
Expected dividend yield	0.00%		0.00%		0.00%

Fair value of the Warrants was calculated as of October 28, 2016 using the methods described in Note 18 using the following assumptions:

Expected volatility	82.54%
Expected life of option, in years		7.0
Risk-free interest rate	1.63%
Expected dividend yield	0.00%