| | Warrants outstanding | | ||||||||
| | | | | | | | Weighted | | ||
| | | | | | Weighted | | average | | ||
| | | | Exercise price | | average | | grant-date fair | | ||
| | Number of | | range per | | exercise price | | value per | | ||
| | warrants | | share | | per share | | share | | ||
| | | | | | | | | | | |
Balance as of December 31, 2013 and 2012 | | 23,334 | | 4.50 | | $ | 4.50 | | $ | 7.93 | |