Stockholders' Equity - Summary of Non-Vested Options (Detail) (USD $)
In Thousands, except Per Share data, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]  
Shares, Non-vested, Beginning balance 276
Shares, Granted 280
Shares, Vested (137)
Shares, Forfeited (7)
Shares, Non-vested, Ending balance 412
Weighted-average grant-date fair value, Non-vested, Beginning balance $ 0.58
Weighted-average grant-date fair value, Granted $ 0.93
Weighted-average grant-date fair value, Vested $ 0.58
Weighted-average grant-date fair value, Forfeited $ 0.58
Weighted-average grant-date fair value, Non-vested, Ending balance $ 0.82