Retirement Plan - Additional Information (Detail) - USD ($) |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
|
| Defined Contribution Plan Disclosure [Line Items] | |||
| Percentage of employer's contribution on employee's base salary | 2.00% | ||
| Contribution expense | $ 200,000 | $ 100,000 | |
| Maximum [Member] | |||
| Defined Contribution Plan Disclosure [Line Items] | |||
| Contribution expense | $ 100,000 | ||