Stockholders' Equity

12 Months Ended

Dec. 31, 2016

Equity [Abstract]

Stockholders' Equity

Note 12. Stockholders’ Equity

Sales Agreement

On May 5, 2016, the Company entered into Amendment No. 2 to the Controlled Equity Offering^SM Sales Agreement, dated August 31, 2012, as previously amended on March 21, 2014, (together, the “Amended Cantor Agreement”) with Cantor Fitzgerald & Co. (“Cantor”) that provides for the issuance and sale of shares of the Company’s common stock over the term of the Amended Cantor Agreement having an aggregate offering price of up to $132.2 million through Cantor. As a result of Amendment No. 2, at May 5, 2016, the Company had $70 million of common stock available to be sold under the Amended Cantor Agreement. Under the Amended Cantor Agreement, Cantor also acts as the Company’s sales agent and receives compensation based on an aggregate of 2% of the gross proceeds on the sale price per share of its common stock. The issuance and sale of these shares by the Company pursuant to the Amended Cantor Agreement are deemed an “at-the-market” offering and are registered under the Securities Act of 1933, as amended. During the year ended December 31, 2016 and 2015, 3.5 million and zero shares, respectively, of the Company’s common stock were sold under the Amended Cantor Agreement for net proceeds of $22.0 million and zero, respectively. At December 31, 2016, the Company had $62.3 million of common stock available to be sold under the Amended Cantor Agreement.

Stockholder Rights Plan

In October 2009, the Company’s Board of Directors adopted an amendment to its 1999 stockholder rights plan, commonly referred to as a “poison pill,” to reduce the exercise price, extend the expiration date and revise certain definitions under the plan. The stockholder rights plan is intended to deter hostile or coercive attempts to acquire the Company. The stockholder rights plan enables stockholders to acquire shares of the Company’s common stock, or the common stock of an acquirer, at a substantial discount to the public market price should any person or group acquire more than 15% of the Company’s common stock without the approval of the Board of Directors under certain circumstances. The Company has designated 250,000 shares of Series C Junior Participating preferred stock for issuance in connection with the stockholder rights plan. As of December 31, 2016, no Series C Junior Participating preferred stock has been issued.

Common Stock and Associated Warrant Liability

In November 2010, the Company issued warrants (“2010 Warrants”) to purchase 3.7 million shares of common stock, exercisable at an exercise price of $3.20 per share. The 2010 Warrants became exercisable on May 15, 2011, and were exercisable for a period of five years from the issue date. In 2015, all outstanding 2010 Warrants were exercised in full. At December 31, 2016, the Company had no outstanding warrants remaining.