Stock Based Compensation - Summary of Stock Option Transactions under Company's Stock Incentive Plans (Detail) - $ / shares |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
|
| Disclosure Of Compensation Related Costs Sharebased Payments [Abstract] | |||
| Shares Outstanding, Beginning Balance | 945,584 | 859,443 | 840,419 |
| Shares, Granted | 339,975 | 235,675 | 188,961 |
| Shares, Exercised | 0 | 0 | 0 |
| Shares, Forfeited | (82,758) | (149,534) | (169,937) |
| Shares Outstanding, Ending Balance | 1,202,801 | 945,584 | 859,443 |
| Shares Vested and unvested options expected to vest as of December 31, 2016 | 1,166,012 | ||
| Weighted Average Exercise Price, Beginning Balance | $ 23.27 | $ 26.58 | $ 31.50 |
| Weighted Average Exercise Price, Granted | 3.51 | 10.06 | 13.99 |
| Weighted Average Exercise Price, Exercised | 0 | 0 | 0 |
| Weighted Average Exercise Price, Forfeited | 24.37 | 21.51 | 36.91 |
| Weighted Average Exercise Price, Ending Balance | 17.61 | $ 23.27 | $ 26.58 |
| Weighted Average Exercise Price, Vested and unvested options expected to vest as of December 31, 2016 | $ 18.00 | ||