8. Common stock

12 Months Ended

Dec. 31, 2015

Notes to Financial Statements

Common stock - Note 8

8. COMMON STOCK

In May 2015, we entered into an ATM agreement with Meyers Associates, L.P. Under the terms of the agreement, we may, from time to time, at our discretion, offer and sell shares of our common stock having an aggregate value of up to $6.0 million. As of December 31, 2015, we have received gross proceeds of approximately $2.3 million before issuance costs of approximately $85,000 from the sale of 742,000 shares of our common stock.

During the year ended December 31, 2015, we received $3.3 million from the exercise of warrants to purchase 1.5 million shares of our common stock, which warrants were issued in connection with earlier financing transactions.

During the three months ended March 31, 2015, we received gross proceeds of $1.0 million as part of an ATM agreement we entered into with Meyers Associates, L.P. in June 2014. We have completed sales under this agreement, having received total proceeds of approximately $4.5 million before issuance costs of approximately $206,000 from the sale of 2.0 million shares of our common stock.

In March 2014, we raised $13.9 million before issuance costs of approximately $1.0 million through an underwritten offering of 7.2 million shares of our common stock and warrants to purchase 2.1 million shares of our common stock.

In February 2014, we issued 3.7 million shares of our common stock under the exchange provisions of the warrants issued in connection with the May and September 2013 financing activities. We recognized a loss of $5.0 million on the exchange as the fair market value of the common stock issued was greater than the obligation recorded due to an increase in our stock price since December 31, 2013.

In September 2013, we raised $6.6 million before issuance costs of approximately $452,000 from the sale of 3.5 million shares of common stock and warrants to purchase up to an aggregate of 2.1 million shares of our common stock in a registered direct offering.

In May 2013, we raised $5.9 million before issuance costs of approximately $362,000 from the sale of 2.6 million shares of common stock and warrants to purchase up to an aggregate of 2.0 million shares of our common stock in a registered direct offering.