Note 8 - Stockholders’ Equity

Stock Options

The Company has an incentive stock plan, the Amended and Restated 2011 Equity Incentive Plan (the “2011 Plan”), and has granted stock options to employees, non-employee directors and consultants from the 2011 Plan. Options granted under the 2011 Plan may be Incentive Stock Options or Non-statutory Stock Options, as determined by the Administrator at the time of grant. On June 19, 2018, the Company’s stockholders approved an amendment to the 2011 Plan to increase the number of shares authorized for issuance under the 2011 Plan to a total of 10,000,000. As of September 30, 2018, there were 3,777,712 shares remaining available for issuance under the 2011 Plan.

During the nine months ended September 30, 2018, the Company granted stock options to employees and non-employee directors to purchase a total of 758,000 shares of the Company’s common stock with grant date prices that ranged between $5.30 to $8.86 per share. The stock options have terms of ten years and are subject to vesting based on continuous service of the awardee over the periods ranging between zero and four years. The stock options have an aggregate grant date fair value of $3,034,559.

Due to the commencement of the clinical study during the quarter ended September 30, 2018, 726,000 stock options the Company granted to its employees in January 2017 met the performance conditions applicable to such options and began vesting. Upon certification of achievement of the performance condition by the compensation committee of the Company’s board of directors on July 18, 2018, 50% of the options became vested. The remaining shares subject to the stock options will vest over a period of 24 months subject to the continuous service of the applicable optionee. The stock options have an exercise price of $2.40 and an aggregate grant date fair value of $2,759,453.

During the nine months ended September 30, 2018, stock options for the purchase of 563,121 shares were exercised for cash proceeds of $446,242.

The Company recorded stock-based compensation as follows:

The following table represents stock option activity for the nine months ended September 30, 2018:

The following table summarizes information on stock options outstanding and exercisable as of September 30, 2018:

Warrants

During the nine months ended September 30, 2018, warrants to purchase 349,315 shares of the Company’s common stock were exercised for aggregate cash proceeds of $678,240.