Warrants

12 Months Ended

Dec. 31, 2015

Warrants.

Warrants

6. Warrants

Common Stock Warrants

During the year ended December 31, 2008, the Company issued warrants to purchase 90,000 shares of common stock for consulting services with an exercise price of $2.04 per share and a ten year term. These warrants vested over four years. During the years ended December 31, 2015, 2014 and 2013, the expense related to the issuances and vesting of these warrants were insignificant. These warrants expired without exercise during the year ended December 31, 2015.