Warrants | Number of warrants | Weighted average exercise price | Expiration date | |||||
Outstanding at December 31, 2012 | 25,841,868 | $ | 0.95 | Various from September 2014 through March 2017 | ||||
Issued | 281,622 | 0.89 | ||||||
Exercised | (1,626,826 | ) | — | |||||
Expired | — | — | ||||||
Outstanding and Exercisable at December 31, 2013 | 24,496,664 | $ | 0.94 | Various from September 2014 through March 2017 | ||||