Related Party Transactions - Additional Information (Detail) - Consulting Agreement [Member] - USD ($) $ in Thousands |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
|
| Related Party Transaction [Line Items] | |||
| Related party transaction, total expenses | $ 154 | $ 164 | $ 169 |
| Related party transaction, due to stockholder | $ 21 | ||