Preferred Stock, Common Stock and Stockholders' Equity - Summary of Common Stock Reserved for Future Issuance (Detail) - shares |
Dec. 31, 2015 |
Dec. 31, 2014 |
|---|---|---|
| Common Stock Reserved for Future Issuance [Line Items] | ||
| Stock options issued and outstanding | 1,037,500 | 683,500 |
| Authorized for future option grants | 78,854 | 188,370 |
| Warrants to purchase common stock | 118,881 | 118,881 |
| Total common stock reserved for future issuance | 1,276,765 | 1,043,457 |
| Authorized for Employee Stock Purchase Plan [Member] | ||
| Common Stock Reserved for Future Issuance [Line Items] | ||
| Total common stock reserved for future issuance | 41,530 | 52,706 |