Common stock	6 Months Ended
Jun. 30, 2016
Equity [Abstract]
Common stock	Common stock In June 2016, we issued and sold in an underwritten public offering an aggregate of 8,222,500 shares of our common stock at $7.00 per share, which included 1,072,500 shares that represented the full exercise of an option to purchase additional shares granted to the underwriters in connection with the offering. The shares included in this offering were registered under the Securities Act of 1933, as amended, or the Securities Act, pursuant to a registration statement on Form S-3 (File No. 333-209778) that the SEC declared effective on May 5, 2016. The offering resulted in $53.9 million of net proceeds, after deducting underwriting discounts and commissions and other offering expenses payable by us. In January 2015, we issued and sold in an underwritten public offering an aggregate of 2,645,000 shares of our common stock at $50 per share, which included 345,000 shares that represented the full exercise of an option to purchase additional shares granted to the underwriters in connection with the offering. The shares included in this offering were registered under the Securities Act pursuant to a registration statement on Form S-3 (File No. 333-200040) that the SEC declared effective on November 21, 2014. The offering resulted in $124.1 million of net proceeds, after deducting underwriting discounts and commissions and other offering expenses payable by us.

Common stock

6 Months Ended

Jun. 30, 2016

In June 2016, we issued and sold in an underwritten public offering an aggregate of 8,222,500 shares of our common stock at $7.00 per share, which included 1,072,500 shares that represented the full exercise of an option to purchase additional shares granted to the underwriters in connection with the offering. The shares included in this offering were registered under the Securities Act of 1933, as amended, or the Securities Act, pursuant to a registration statement on Form S-3 (File No. 333-209778) that the SEC declared effective on May 5, 2016. The offering resulted in $53.9 million of net proceeds, after deducting underwriting discounts and commissions and other offering expenses payable by us.

In January 2015, we issued and sold in an underwritten public offering an aggregate of 2,645,000 shares of our common stock at $50 per share, which included 345,000 shares that represented the full exercise of an option to purchase additional shares granted to the underwriters in connection with the offering. The shares included in this offering were registered under the Securities Act pursuant to a registration statement on Form S-3 (File No. 333-200040) that the SEC declared effective on November 21, 2014. The offering resulted in $124.1 million of net proceeds, after deducting underwriting discounts and commissions and other offering expenses payable by us.