Stockholders' Equity

12 Months Ended

Dec. 31, 2017

Stockholders' Equity

Stockholders' Equity

(10) Stockholders' Equity

Common Stock

        In December 2013, the Company filed an automatic shelf registration statement with the Securities and Exchange Commission to register for sale any combination of the types of securities described in the shelf registration statement. In December 2016, the Company filed a new shelf registration statement with the Securities and Exchange Commission to register for sale any combination of the types of securities described in the shelf registration statement up to a maximum aggregate offering price of $250 million. Such registration statement was declared effective on February 13, 2017.

        In May 2016, the Company entered into an agreement with Cantor Fitzgerald & Co. ("Cantor") to allow the Company to issue and sell shares of its common stock having an aggregate offering price of up to $60.0 million from time to time through Cantor, acting as agent. In November 2017, the Company filed a prospectus supplement registering the offer and sale of shares of common stock of up to an additional $75.0 million under the agreement with Cantor. During the years ended December 31, 2017 and 2016, the Company issued 17,722,863 and 3,303,800 shares of its common stock, respectively, under this controlled equity offering sales agreement with Cantor resulting in net proceeds to the Company of $51.0 million and $13.9 million, respectively, after deducting commission and offering expenses. At December 31, 2017, the Company had $67.6 million remaining in aggregate gross offering price available under the Cantor agreement. From January 1, 2018 through February 28, 2018, the Company issued 2,401,847 shares of its common stock resulting in net proceeds to the Company of $6.1 million.

        During the year ended December 31, 2015, the Company issued 8,337,500 shares of its common stock in underwritten public offerings resulting in net proceeds to the Company of $188.8 million after deducting underwriting fees and offering expenses.

Convertible Preferred Stock

        At December 31, 2017, the Company had authorized 3,000,000 shares of preferred stock all of which have been designated Class C Preferred Stock including 350,000 shares which have been designated Series C-1 Junior Participating Cumulative Preferred Stock (the "Series C-1 Preferred Stock"). No shares of Series C-1 Preferred Stock were outstanding at December 31, 2017 or 2016.