Stockholders' Equity - Summary of Warrant Activity (Details) |
12 Months Ended | ||
|---|---|---|---|
|
Dec. 31, 2015
$ / shares
shares
|
Dec. 31, 2014
$ / shares
shares
|
Dec. 31, 2013
$ / shares
shares
|
|
| Warrants Outstanding | |||
| Beginning balance (in shares) | shares | 969,549 | 1,107,549 | 1,305,638 |
| Warrants issued (in shares) | shares | 147,000 | 2,549 | |
| Warrants expired (in shares) | shares | (205,000) | (285,000) | (200,638) |
| Warrants exercised (in shares) | shares | (638,189) | ||
| Warrants canceled/forfeited (in shares) | shares | (112,110) | ||
| Ending balance (in shares) | shares | 14,250 | 969,549 | 1,107,549 |
| Weighted Average Exercise Price During Period | |||
| Beginning balance (in dollars per share) | $ / shares | 4.61 | 4.41 | 7.60 |
| Warrants issued (in dollars per share) | $ / shares | 4.65 | 3.49 | |
| Warrants expired (in dollars per share) | $ / shares | 4.20 | 3.87 | 19.70 |
| Warrants exercised (in dollars per share) | $ / shares | 4.58 | ||
| Warrants canceled/forfeited (in dollars per share) | $ / shares | 5.54 | ||
| Ending balance (in dollars per share) | $ / shares | 4.30 | 4.61 | 4.41 |