Consolidated Balance Sheets (Parenthetical) - $ / shares |
Dec. 31, 2015 |
Dec. 31, 2014 |
|---|---|---|
| Consolidated Balance Sheets | ||
| Preferred stock, par value (in dollars per share) | $ 0.001 | $ 0.001 |
| Preferred stock, shares authorized | 5,000,000 | 5,000,000 |
| Preferred stock, shares issued | 0 | 0 |
| Preferred stock, shares outstanding | 0 | 0 |
| Common stock, par value (in dollars per share) | $ 0.001 | $ 0.001 |
| Common stock, shares authorized | 200,000,000 | 200,000,000 |
| Common stock, shares issued | 45,776,455 | 40,735,069 |
| Common stock, shares outstanding | 45,776,455 | 40,735,069 |