General form of registration statement for all companies including face-amount certificate companies

Other (Expense)/Income - Additional Information (Detail)

v3.21.2
Other (Expense)/Income - Additional Information (Detail)
 1 Months Ended 9 Months Ended 12 Months Ended
Feb. 18, 2021
USD ($)
Feb. 03, 2021
USD ($)
TRANCHE
shares
Feb. 28, 2021
USD ($)
Day
Sep. 30, 2021
USD ($)
TRANCHE
Sep. 30, 2020
USD ($)
Dec. 31, 2019
USD ($)
Jun. 30, 2021
USD ($)
Feb. 02, 2021
USD ($)
Non Operating Expense Income [Line Items]                
Stock Issued During Period, Value, Conversion of Convertible Securities           $ 36,236,000    
Payments of Debt Issuance Costs       $ 6,238,000 $ 108,000      
Debt Instrument, Number of Tranches   2 2 3        
Rights Offering [Member]                
Non Operating Expense Income [Line Items]                
Loss on Debt Issuance   $ 3,000,000            
Bridge Notes Payable [Member]                
Non Operating Expense Income [Line Items]                
Stock Issued During Period, Value, Conversion of Convertible Securities       $ 77,097,000        
Debt Issuance Costs, Net   $ 47,600,000         $ 100,000  
Debt Issuance Costs Shares Shares Issued | shares   8,500,000            
Debt Issuance Costs, Value, Shares Issued   $ 43,900,000            
Payments of Debt Issuance Costs   3,700,000            
Bridge Notes Payable [Member] | Common Stock [Member]                
Non Operating Expense Income [Line Items]                
Stock Issued During Period, Value, Conversion of Convertible Securities     $ 59,800          
Bridge Notes Payable [Member] | Incentive Common Stock [Member]                
Non Operating Expense Income [Line Items]                
Stock Issued During Period, Value, Conversion of Convertible Securities   $ 2,600,000            
Conversion of bridge notes and accrued interest into common stock (in shares) | shares   300,000            
Bridge Notes Payable [Member] | Incentive Warrant [Member]                
Non Operating Expense Income [Line Items]                
Stock Issued During Period, Value, Conversion of Convertible Securities   $ 500,000            
Conversion of bridge notes and accrued interest into common stock (in shares) | shares   51,000            
Bridge Notes Payable [Member] | Warrant [Member]                
Non Operating Expense Income [Line Items]                
Stock Issued During Period, Value, Conversion of Convertible Securities     3,900,000          
Warrant Issued During Period, Value, Conversion of Convertible Securities     18,400,000          
Tranche Two Of Bridge Notes Member [Member]                
Non Operating Expense Income [Line Items]                
Loss on Debt Issuance $ 12,200,000              
Bridge Notes Rights Offering [Member] | Common Class A [Member]                
Non Operating Expense Income [Line Items]                
Stock Issued During Period, Value, Conversion of Convertible Securities     11,500          
Convertible Debt [Member] | Bridge Notes Payable [Member]                
Non Operating Expense Income [Line Items]                
Debt Instrument, Face Amount 40,000,000.0   18,100,000       500,000 $ 60,000,000
Debt Instrument, Fair Value Disclosure $ 52,200,000   $ 24,200,000       $ 600,000  
Tranche One Of Bridge Notes [Member] | Bridge Notes Payable [Member]                
Non Operating Expense Income [Line Items]                
Loss on Debt Issuance   $ 84,300,000