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Fair Value of Financial Instruments - Additional Information (Detail) - USD ($)
Sep. 30, 2021
Dec. 31, 2020
Sep. 30, 2020
Fair Value Of Financial Instruments [Line Items]      
Cash and cash equivalents $ 51,740,000 $ 67,005,000 $ 52,398,000
Restricted cash   158,000 $ 316,000
Short-term investments 87,312,000    
Long-term investments 42,059,000    
Money Market Funds      
Fair Value Of Financial Instruments [Line Items]      
Cash and cash equivalents 51,700,000 67,000,000.0  
Restricted cash $ 0 $ 200,000