Net Loss Per Share (Schedule of Antidilutive Securities Excluded From Earnings Per Share) (Details) - Common stock - shares |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2016 |
Sep. 30, 2015 |
Sep. 30, 2016 |
Sep. 30, 2015 |
|
| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||||
| Antidilutive securities excluded from computation of earnings per share (in shares) | 4,668,077 | 3,337,893 | 4,677,467 | 3,088,773 |
| Common stock warrants | ||||
| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||||
| Antidilutive securities excluded from computation of earnings per share (in shares) | 1,021,651 | 997,839 | 1,024,705 | 954,345 |
| Common stock options | ||||
| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] | ||||
| Antidilutive securities excluded from computation of earnings per share (in shares) | 3,646,426 | 2,340,054 | 3,652,762 | 2,134,428 |