Stockholders' Equity

6 Months Ended

Jun. 30, 2019

Stockholders' Equity Note [Abstract]

Stockholders' Equity

Stockholders’ Equity

Common Stock 

On October 11, 2016, the Company completed an underwritten public offering of 10,000,000 shares of its common stock and accompanying warrants to purchase 10,000,000 shares of common stock at a purchase price of $3.00 per unit, comprising of one share of common stock and one warrant. The change in fair value of the warrant liabilities for the three and six months ended June 30, 2018, resulted in a loss of approximately $58.9 million and $49.0 million, respectively, which has been recognized in the accompanying condensed consolidated statements of comprehensive loss. During 2018, all of the warrants were exercised. As of June 30, 2019 and December 31, 2018, there were no warrants outstanding.

At-the-market Offering

On March 29, 2019, the Company entered into a sales agreement (the "ATM Agreement") with Cowen and Company, LLC ("Cowen") to issue and sell shares of the Company’s common stock, par value $0.01 per share, having an aggregate offering price of up to $150,000,000, from time to time during the term of the ATM Agreement, through an “at-the-market” equity offering program at the Company's sole discretion, under which Cowen will act as the Company’s agent and/or principal. The Company will pay Cowen a commission up to 3.0% of the gross sales proceeds of any common stock sold through Cowen under the ATM Agreement. During the three and six months ended June 30, 2019, the Company sold 370,920 shares of common stock with net proceeds of $5.8 million at a weighted average price of $15.95 (excluding commissions) under the ATM Agreement.

Treasury Stock

During the six months ended June 30, 2019, there were 84,896 shares received in connection with a non-cash equity transaction related to the Company's Plan.