Stock-based Compensation - Stock-based Compensation Expense Recognized (Detail) - USD ($) |
3 Months Ended | |
|---|---|---|
Mar. 31, 2016 |
Mar. 31, 2015 |
|
| Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] | ||
| Total Stock based compensation | $ 205,761 | $ 112,140 |
| Research and Development [Member] | ||
| Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] | ||
| Total Stock based compensation | 33,633 | 20,917 |
| Selling, General and Administrative [Member] | ||
| Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] | ||
| Total Stock based compensation | $ 172,128 | $ 91,223 |