Summary of Significant Accounting Policies; Prior Period Reclassification - Summary of Financial Assets and Liabilities Measured at Fair Value (Detail) - Recurring [Member] - Level 3 [Member] - Derivative Liability [Member] $ in Thousands |
12 Months Ended |
|---|---|
|
Dec. 31, 2019
USD ($)
| |
| Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items] | |
| Initial recognition of conversion features and warrants | $ 7,954 |
| Change in fair value of derivative liability | (6,233) |
| Balance, December 31, 2019 | $ 1,721 |