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Fair Value Measurements - Additional Information (Detail) - USD ($)
9 Months Ended 12 Months Ended
Sep. 30, 2021
Dec. 31, 2020
Fair Value Disclosures [Abstract]    
Fair value transfers into Level 3 $ 0 $ 0
Fair value transfers out of Level 3 0 0
Assets or liabilities measured at fair value on a non-recurring basis.   $ 0
Non-cash impairment charge 8,070,000  
Fair value of impaired assets $ 3,300,000