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Inventories - Additional Information (Detail) - USD ($)
3 Months Ended 6 Months Ended
Jun. 30, 2021
Jun. 30, 2021
Jun. 30, 2020
Dec. 31, 2020
Inventory [Line Items]        
Inventory write-off $ 0 $ 0 $ 496,000  
Pre-launch Inventory        
Inventory [Line Items]        
Raw materials inventory $ 800,000 $ 800,000   $ 800,000