Warrants	12 Months Ended
Dec. 31, 2015
Equity [Abstract]
Warrants	10. Warrants In October 2009, we issued a total of 8,107,012 shares of our common stock and warrants to purchase up to an additional 7,296,312 shares of our common stock in a private placement. These securities were sold as units with each unit consisting of one share of common stock and a warrant to purchase 0.9 shares of common stock at a purchase price of $2.4325 per unit. The warrants issued are cash or net exercisable with an exercise price of $2.77 per share and will expire in October 2016. At December 31, 2015, 729,627 remained outstanding and exercisable. In May 2010, in conjunction with a Loan Agreement with Hercules Technology Growth Capital, or Hercules, we issued to Hercules a five-year warrant to purchase 37,639 shares of our common stock at a price of $26.90 per share. The warrant expired in May 2015. In August 2010, we issued an aggregate of 668,518 shares of our common stock and warrants to purchase up to an additional 334,258 shares of our common stock in a registered direct offering. These securities were sold as units with each unit consisting of (i) one share of common stock and (ii) a warrant to purchase 0.5 of a share of common stock, at a purchase price of $27.00 per unit. The warrants were exercisable at $33.00 per share and expired in August 2015. In May 2011, we issued an aggregate of 1,192,703 shares of our common stock and warrants to purchase up to an additional 417,445 shares of our common stock in a registered direct offering. The warrants are exercisable at $17.55 per share and will expire in May 2016. At December 31, 2015, these warrants remained outstanding and exercisable. In February 2012, we issued an aggregate of 4,400,000 shares of our common stock and warrants to purchase up to an additional 4,400,000 shares of our common stock in an underwritten public offering. The warrants are exercisable beginning February 24, 2013, at an exercise price of $5.00 per share, and will expire on February 23, 2017. At December 31, 2015, these warrants remained outstanding and exercisable. In March 2014, in conjunction with the royalty securitization financing, we issued to the debt holders a five-year warrant to purchase 345,661 shares of our common stock at a price of $0.01 per share. The warrant expires in March 2019. At December 31, 2015, these warrants remained outstanding and exercisable. All outstanding warrants include a provision that allows the warrant holder to net share settle the warrant. In no circumstances will we issue shares in excess of the number of shares underlying the warrant. The outstanding warrants are classified as additional paid in capital and are indexed to our common stock.

10. Warrants

In October 2009, we issued a total of 8,107,012 shares of our common stock and warrants to purchase up to an additional 7,296,312 shares of our common stock in a private placement. These securities were sold as units with each unit consisting of one share of common stock and a warrant to purchase 0.9 shares of common stock at a purchase price of $2.4325 per unit. The warrants issued are cash or net exercisable with an exercise price of $2.77 per share and will expire in October 2016. At December 31, 2015, 729,627 remained outstanding and exercisable.

In May 2010, in conjunction with a Loan Agreement with Hercules Technology Growth Capital, or Hercules, we issued to Hercules a five-year warrant to purchase 37,639 shares of our common stock at a price of $26.90 per share. The warrant expired in May 2015.

In August 2010, we issued an aggregate of 668,518 shares of our common stock and warrants to purchase up to an additional 334,258 shares of our common stock in a registered direct offering. These securities were sold as units with each unit consisting of (i) one share of common stock and (ii) a warrant to purchase 0.5 of a share of common stock, at a purchase price of $27.00 per unit. The warrants were exercisable at $33.00 per share and expired in August 2015.

In May 2011, we issued an aggregate of 1,192,703 shares of our common stock and warrants to purchase up to an additional 417,445 shares of our common stock in a registered direct offering. The warrants are exercisable at $17.55 per share and will expire in May 2016. At December 31, 2015, these warrants remained outstanding and exercisable.

In February 2012, we issued an aggregate of 4,400,000 shares of our common stock and warrants to purchase up to an additional 4,400,000 shares of our common stock in an underwritten public offering. The warrants are exercisable beginning February 24, 2013, at an exercise price of $5.00 per share, and will expire on February 23, 2017. At December 31, 2015, these warrants remained outstanding and exercisable.

In March 2014, in conjunction with the royalty securitization financing, we issued to the debt holders a five-year warrant to purchase 345,661 shares of our common stock at a price of $0.01 per share. The warrant expires in March 2019. At December 31, 2015, these warrants remained outstanding and exercisable.

All outstanding warrants include a provision that allows the warrant holder to net share settle the warrant. In no circumstances will we issue shares in excess of the number of shares underlying the warrant. The outstanding warrants are classified as additional paid in capital and are indexed to our common stock.