Years ended December 31, | ||||||
2017 | 2016 | |||||
Expected dividend yield | (a) | 0.00 | % | 0.00 | % | |
Expected volatility | (b) | 137.60 | % | 115.10 | % | |
Risk-free annual interest rate | (c) | 1.53 | % | 1.80 | % | |
Expected life (years) | (d) | 3.26 | 4.92 | |||
Weighted average share price | $2.05 | $3.47 | ||||
Weighted average exercise price | $2.05 | $3.47 | ||||
Weighted average grant date fair value | $1.62 | $2.80 | ||||
(a) | The Company has not paid dividends and it does not intend to pay dividends in the foreseeable future. |
(b) | Based on the historical volatility of the Company's stock price over the most recent period consistent with the expected life of the stock options, as well as on future expectations. |
(c) | Based on United States Treasury Government Bond interest rates with a term that is consistent with the expected life of the stock options. |
(d) | Based upon historical data related to the exercise of stock options, on post-vesting employment terminations and on future expectations related to exercise behavior. |