Note 4 - Stock-based Compensation

We did not grant any stock options to employees or non-employees during the three months ended March 31, 2019 or 2018. At March 31, 2019, we had outstanding options to purchase 384,400 shares of our common stock of which options for the purchase of 9,000 shares of our common stock were vested. We recorded $58,559 of stock-based compensation expense for the three months ended March 31, 2019 as general and administrative expense. No expense was recorded during the three months ended March 31, 2018 since we had not stock options outstanding at March 31, 2018.