Number of Warrants | Weighted- Average Exercise Price per Warrant | Number of Contingent Warrants | Weighted- Average Exercise Price per Contingent Warrant | ||||||||||
Warrants outstanding at January 1, 2011 | 6,003,924 | $ | 1.21 | 1,252,990 | $ | 0.01 | |||||||
Issued in connection with private placement of common stock | 1,889,161 | 1.50 | 1,889,162 | 0.01 | |||||||||
Issued in connection with convertible promissory notes | 203,332 | 1.50 | 203,332 | 0.01 | |||||||||
Issued in connection with line of credit with related party | — | — | 650,000 | 0.01 | |||||||||
Issued in connection with Senior Secured Promissory Notes | 1,250,000 | 0.01 | 1,250,000 | 0.01 | |||||||||
Placement agent | 42,400 | 1.09 | — | — | |||||||||
Warrants outstanding at December 31, 2011 | 9,388,817 | $ | 1.00 | 5,245,484 | $ | 0.01 | |||||||
Warrants outstanding at January 1, 2012 | 9,388,817 | $ | 1.00 | 5,245,484 | $ | 0.01 | |||||||
Warrants issued: | |||||||||||||
Vested contingent warrants related to private placement of common stock | 1,672,743 | 0.01 | (1,672,743 | ) | 0.01 | ||||||||
Vested contingent warrants related to line of credit with related party | 325,000 | 0.01 | (325,000 | ) | 0.01 | ||||||||
Contingent warrants voided | — | — | (3,247,741 | ) | 0.01 | ||||||||
Warrants exercised: | |||||||||||||
Contingent warrants related to convertible note | (1,249,750 | ) | 0.01 | — | — | ||||||||
Contingent warrants related to private placement of common stock | (1,608,802 | ) | 0.01 | — | — | ||||||||
Contingent warrants related to line of credit with related party | (325,000 | ) | 0.01 | — | — | ||||||||
Callable warrants | (3,288,733 | ) | 1.50 | — | — | ||||||||
Other | (1,703,568 | ) | 0.63 | — | — | ||||||||
Warrants expired | (10,000 | ) | 1.00 | — | — | ||||||||
Warrants redeemed for cashless exercises | (14,789 | ) | 0.53 | — | — | ||||||||
Repurchased callable warrants | (56,750 | ) | 1.50 | — | — | ||||||||
Warrants outstanding at December 31, 2012 | 3,129,168 | $ | 1.04 | — | $ | — | |||||||
Warrants outstanding at January 1, 2013 | 3,129,168 | 1.04 | — | — | |||||||||
Warrants exercised: | |||||||||||||
Other | (1,844,352 | ) | 1.14 | — | — | ||||||||
Warrants outstanding at December 31, 2013 | 1,284,816 | $ | 0.90 | — | $ | — | |||||||