The Company periodically issues stock options and warrants to employees and non-employees in capital raising transactions, for services and for financing costs. Options vest and expire according to terms established at the grant date.

Options

The Company issues stock options to employees, directors and consultants under its 2004 Stock Option Plan (the Plan), and in some cases issues stock options outside of the Plan. The Company could issue options under the Plan to acquire up to 7,000,000 shares of common stock as amended in May 2006.

From the Plan’s inception in 2004 up to June 30, 2014, the Company granted options to purchase 9,619,867 shares under the Plan, of which options to purchase 4,328,574 shares were subsequently cancelled or forfeited and made available for grants under the Plan. As of June 30, 2014, options to purchase 1,268,333 shares previously issued under the Plan had been exercised, options to purchase 4,022,960 shares were issued and outstanding and 1,708,707 shares were available to be granted under the Plan.

From the Company’s inception in February 1998 up to June 30, 2014, options to purchase a total of 37,050,000 shares were granted outside of the Plan, of which, options to purchase 17,485,000 shares were subsequently cancelled or forfeited. As of June 30, 2014, there were 16,705,000 options to purchase shares of common stock issued outside of the plan.

Employee options vest according to the terms of the specific grant and expire from 5 to 10 years from date of grant. Non-employee option grants have vested upon issuance and up to 2 years from the date of grant. The weighted-average, remaining contractual life of employee and non-employee options outstanding at June 30, 2014 was 6.7 years. Stock option activity for the period December 31, 2013 up to June 30, 2014, was as follows: 

The weighted average exercise prices, remaining contractual lives for options granted, exercisable, and expected to vest as of June 30, 2014 were as follows:

At June 30, 2014 the aggregate intrinsic value of the options outstanding was $11,451,670. Future unamortized compensation expense on the unvested outstanding options at June 30, 2014 is approximately $319,000.

During the six month period ending June 30, 2014:

During the three and six month periods ended June 30, 2014 the Company recognized compensation costs based on the fair value of options that vested of $285,923 and $401,575, respectively. During the three and six month periods ended June 30, 2013, the Company recognized $417,162 and $821,749, respectively, of such costs.

Warrants

The following table summarizes certain information about the Company’s stock purchase warrants activity for the period starting December 31, 2013 up to June 30, 2014.

The weighted average exercise prices, remaining contractual lives for warrants granted, exercisable, and expected to vest as of June 30, 2014 were as follows:

At June 30, 2014, the aggregate intrinsic value of the warrants outstanding was $2,812,462. Future unamortized compensation expense on the unvested outstanding warrants at June 30, 2014 is approximately $45,000.

During the six month period ending June 30, 2014:

During the six months ended June 30, 2014 and 2013, the Company recognized compensation costs of $35,647 and $100,981, respectively, based on the vested fair value of warrants granted to consultants and an employee.