Accrued Expenses - Schedule of Accrued Expenses (Detail) - USD ($) $ in Thousands |
Jun. 30, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
|---|---|---|---|
| Accrued Liabilities and Other Liabilities [Abstract] | |||
| Employee compensation and benefits | $ 725 | $ 528 | |
| Clinical development expenses | 225 | 186 | |
| Professional fees | 126 | 165 | |
| Research and development costs | 20 | 118 | |
| Other | 10 | 5 | |
| Total accrued expenses | $ 1,256 | $ 1,106 | $ 1,002 |