Commitments and Contingencies - Additional Information (Detail)
12 Months Ended
Jan. 01, 2021
USD ($)
Dec. 31, 2021
USD ($)
claim
vehicle
Dec. 31, 2020
USD ($)
claim
Apr. 14, 2020
USD ($)
ft²
Dec. 31, 2019
Oct. 03, 2019
USD ($)
ft²
Loss Contingencies [Line Items]            
Weighted Average Remaining Lease Term (in years)   3 years 6 months 29 days 4 years 5 months 4 days      
Vehicles delivered | vehicle   72        
Restricted cash   $ 5,056,000 $ 22,559,000      
Square footage | ft²       8,816   24,474
Renewal period           5 years
Purchase obligation, purchases during the period   $ 3,000,000 3,700,000      
Claims | claim   0        
Rush University | Maximum            
Loss Contingencies [Line Items]            
Maximum earned royalties $ 100,000          
Rush University | Royalty Agreement Terms            
Loss Contingencies [Line Items]            
Minimum annual royalty amount $ 100,000          
Royalty cost   $ 200,000 $ 0      
Securities Deposit            
Loss Contingencies [Line Items]            
Claims | claim     0      
Letter of Credit            
Loss Contingencies [Line Items]            
Security deposit       $ 50,000   $ 750,000
Fleet lease | Letter of Credit            
Loss Contingencies [Line Items]            
Security deposit   300,000        
Office lease | Letter of Credit            
Loss Contingencies [Line Items]            
Security deposit   800,000        
Securities Deposit | Fleet lease            
Loss Contingencies [Line Items]            
Restricted cash   300,000 $ 300,000      
Securities Deposit | Office lease            
Loss Contingencies [Line Items]            
Restricted cash   $ 800,000 $ 800,000      
Lease Contract Term One | Fleet lease            
Loss Contingencies [Line Items]            
Weighted Average Remaining Lease Term (in years)         24 months  
Lease Contract Term Two | Fleet lease            
Loss Contingencies [Line Items]            
Weighted Average Remaining Lease Term (in years)         36 months