Financings	12 Months Ended
Dec. 31, 2016
Financings
Financings	15. Financings October 13, 2016 Follow-on Underwritten Public Offering On October 13, 2016, the Company closed a follow-on underwritten public offering, in which it sold 25,000,000 shares of common stock at a price to the public of $2.00 per share for aggregate gross proceeds of $50.0 million. On October 28, 2016, the Company sold an additional 1,225,243 shares of common stock pursuant to the underwriters’ 30-day option to purchase additional shares at the public offering price less the underwriting discount. The net proceeds to the Company from the offering, including the exercise by the underwriters of their option to purchase additional shares and after deducting underwriters’ discounts and commissions and other offering costs and expenses, were approximately $48.8 million. Investment funds affiliated with Baker Brothers and Pillar Invest Corporation, two of the Company’s principal stockholders, and certain members of the Company’s board of directors, purchased 5,125,000 shares in this offering at the $2.00 per share purchase price. February 19, 2015 Follow-on Underwritten Public Offering On February 19, 2015, the Company closed a follow-on underwritten public offering, in which it sold 23,000,000 shares of common stock at a price to the public of $3.75 per share for aggregate gross proceeds of $86.3 million. The net proceeds to the Company from the offering, after deducting underwriters’ discounts and commissions and other offering costs and expenses, were $80.6 million. Investment funds affiliated with Baker Brothers and two members of the Company’s board of directors purchased 5,333,333 shares in this offering at the $3.75 per share purchase price. On February 19, 2015, Baker Brothers held 6,965,432 shares of the Company’s common stock, warrants to purchase up to 20,316,327 shares of the Company’s common stock at an exercise price of $0.47 per share and pre-funded warrants to purchase up to 22,151,052 shares of the Company’s common stock at an exercise price of $0.01 per share. February 10, 2014 Follow-on Underwritten Public Offering On February 10, 2014, the Company closed a follow-on underwritten public offering, in which it sold 7,867,438 shares of common stock at a price to the public of $4.00 per share and pre-funded warrants to purchase up to 2,158,750 shares of common stock at a price to the public of $3.99 per share for aggregate gross proceeds of $40.1 million. The pre-funded warrants have an exercise price of $0.01 per share and will expire if not exercised by February 10, 2021. The net proceeds to the Company from the offering, after deducting underwriters’ discounts and commissions and other offering costs and expenses and excluding the proceeds of the exercise of the warrants, if any, were approximately $37.2 million.

15. Financings

October 13, 2016 Follow-on Underwritten Public Offering

On October 13, 2016, the Company closed a follow-on underwritten public offering, in which it sold 25,000,000 shares of common stock at a price to the public of $2.00 per share for aggregate gross proceeds of $50.0 million. On October 28, 2016, the Company sold an additional 1,225,243 shares of common stock pursuant to the underwriters’ 30-day option to purchase additional shares at the public offering price less the underwriting discount. The net proceeds to the Company from the offering, including the exercise by the underwriters of their option to purchase additional shares and after deducting underwriters’ discounts and commissions and other offering costs and expenses, were approximately $48.8 million. Investment funds affiliated with Baker Brothers and Pillar Invest Corporation, two of the Company’s principal stockholders, and certain members of the Company’s board of directors, purchased 5,125,000 shares in this offering at the $2.00 per share purchase price.

February 19, 2015 Follow-on Underwritten Public Offering

On February 19, 2015, the Company closed a follow-on underwritten public offering, in which it sold 23,000,000 shares of common stock at a price to the public of $3.75 per share for aggregate gross proceeds of $86.3 million. The net proceeds to the Company from the offering, after deducting underwriters’ discounts and commissions and other offering costs and expenses, were $80.6 million. Investment funds affiliated with Baker Brothers and two members of the Company’s board of directors purchased 5,333,333 shares in this offering at the $3.75 per share purchase price.

On February 19, 2015, Baker Brothers held 6,965,432 shares of the Company’s common stock, warrants to purchase up to 20,316,327 shares of the Company’s common stock at an exercise price of $0.47 per share and pre-funded warrants to purchase up to 22,151,052 shares of the Company’s common stock at an exercise price of $0.01 per share.

February 10, 2014 Follow-on Underwritten Public Offering

On February 10, 2014, the Company closed a follow-on underwritten public offering, in which it sold 7,867,438 shares of common stock at a price to the public of $4.00 per share and pre-funded warrants to purchase up to 2,158,750 shares of common stock at a price to the public of $3.99 per share for aggregate gross proceeds of $40.1 million. The pre-funded warrants have an exercise price of $0.01 per share and will expire if not exercised by February 10, 2021. The net proceeds to the Company from the offering, after deducting underwriters’ discounts and commissions and other offering costs and expenses and excluding the proceeds of the exercise of the warrants, if any, were approximately $37.2 million.