Furniture, Equipment and Leasehold Improvements, Net - Additional Information (Detail) - USD ($) $ in Thousands  | 
3 Months Ended | |
|---|---|---|
Mar. 31, 2020  | 
Mar. 31, 2019  | 
|
| Property Plant And Equipment [Abstract] | ||
| Depreciation expense | $ 273 | $ 163 | 
| Leased assets write off | $ 310 | |
| X | ||||||||||
- Definition Write off of leased assets. No definition available. 
  | 
| X | ||||||||||
- Definition The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
  | 
| X | ||||||||||
- References No definition available. 
  |