13.	Common Stock

Common Stock Outstanding

As of December 31, 2017, there were 61,532,812 shares of our common stock outstanding.

On November 3, 2017, we entered into an At Market Sales Agreement (“2017 ATM Agreement”) with Cowen and Company, LLC (“Cowen”) under which we may offer and sell from time to time at our sole discretion, shares of our common stock having an aggregate offering price up to $150 million through Cowen as our sales agent. We pay Cowen a commission of up to 3% of the gross sales proceeds of any common stock sold through Cowen under the 2017 ATM Agreement. As of December 31, 2017, we received net cash proceeds of $16.9 million resulting from sales of 840,774 shares of our common stock.

In August 2017, we completed an underwritten public offering of 5,750,000 shares of our common stock, including 750,000 shares sold pursuant to the full exercise of an overallotment option previously granted to the underwriters. All of the shares were offered at a price to the public of $15.00 per share. The net proceeds to us from this offering were approximately $80.8 million, after deducting the underwriting discount and other estimated offering expenses payable by us.

As of December 31, 2017, we received net cash proceeds of $88.2 million from sales of 15,997,202 shares of our common stock under a now terminated At Market Sales Agreement (“2015 ATM Agreement”).