Summary of Significant Accounting Policies; Prior Period Reclassification - Reconciliation of Cash and Restricted Cash (Detail) - USD ($) $ in Thousands |
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|---|---|---|---|
| Regulatory Assets [Abstract] | |||
| Cash and cash equivalents | $ 2,232 | $ 1,147 | |
| Restricted cash (short term) | 1,196 | 2,012 | |
| Total | $ 3,428 | $ 3,159 | $ 1,279 |