Stockholders' Equity (Deficit) (Schedule of Stock Option Activity) (Details) - USD ($)
|
9 Months Ended |
12 Months Ended |
Sep. 30, 2015 |
Dec. 31, 2014 |
Dec. 31, 2013 |
| Shares |
|
|
|
| Outstanding, beginning balance |
1,018,590
|
633,482
|
590,047
|
| Granted |
277,875
|
507,879
|
186,736
|
| Exercised |
(10,272)
|
(78,664)
|
(80,706)
|
| Forfeited |
(179,298)
|
(44,107)
|
(62,595)
|
| Outstanding, ending balance |
1,106,895
|
1,018,590
|
633,482
|
| Weighted Average Exercise Price |
|
|
|
| Outstanding, beginning balance |
$ 5.04
|
$ 3.36
|
$ 0.71
|
| Granted |
6.09
|
6.30
|
10.07
|
| Exercised |
1.97
|
0.60
|
0.67
|
| Forfeited |
6.50
|
3.19
|
1.96
|
| Outstanding, ending balance |
5.10
|
$ 5.04
|
3.36
|
| Fair value of stock options vested |
|
$ 1,704,121
|
|
| Weighted average grant-date fair value |
$ 3.33
|
$ 5.66
|
$ 8.51
|
| Options Outstanding, Weighted Average Remaining Contractual Life (Years) |
7 years 4 months 24 days
|
|
|
| Options Vested, shares |
649,421
|
|
|
| Options Vested, Weighted Average Remaining Contractual Life |
6 years 2 months 12 days
|
|
|
| Options Vested, Weighted Average Exercise Price |
$ 3.89
|
|
|
| unrecognized stock-based compensation expense, recognition period |
15 months 24 days
|
14 months 27 days
|
|
| Unrecognized stock-based compensation expense |
$ 3,114,452
|
$ 3,872,221
|
|