Income Taxes - Schedule of Reconciliation of Federal Statutory Income Tax Rate to Effective Tax Rate (Detail) |
12 Months Ended | |
|---|---|---|
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| Effective Income Tax Rate Reconciliation [Line Items] | ||
| Statutory Federal income tax rate | 34.00% | 34.00% |
| State income taxes - net of Federal tax benefit | 0.80% | 1.50% |
| Other permanent differences | (8.10%) | (3.50%) |
| Valuation allowances | (37.00%) | (40.20%) |
| Effective tax rate for the year | 0.20% | 0.20% |
| U.S. Federal [Member] | ||
| Effective Income Tax Rate Reconciliation [Line Items] | ||
| Research and development | 10.30% | 8.20% |
| Foreign [Member] | ||
| Effective Income Tax Rate Reconciliation [Line Items] | ||
| Research and development | 0.20% | 0.20% |