Stock Plans, Share-Based Payments and Warrants - Summary of Options Exercisable Vested and Expected to Vest (Details) - $ / shares |
Dec. 31, 2017 |
Dec. 31, 2016 |
|---|---|---|
| Disclosure of Compensation Related Costs, Share-based Payments [Abstract] | ||
| Shares, Exercisable | 2,271,527 | 1,866,019 |
| Shares, Vested and expected to vest | 6,509,821 | 4,434,220 |
| Weighted Average Exercise Price, Exercisable | $ 0.65 | $ 0.70 |
| Weighted Average Exercise Price, Vested and expected to vest | $ 0.55 | $ 0.61 |