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Stock-Based Compensation - Schedule of Restricted Stock Units Activity (Details) - Restricted Stock Units (RSUs) [Member] - $ / shares
9 Months Ended 12 Months Ended
Sep. 30, 2021
Dec. 31, 2020
Dec. 31, 2019
Restricted Stock Units      
Beginning balance 33,548 10,864 59,767
Granted 29,614 32,019 12,010
Vested and released   (7,906) (48,269)
Vested (1,845)    
Forfeited (15,485) (1,429) (12,644)
Ending balance 45,832 33,548 10,864
Weighted Average Grant Date Fair Value      
Beginning balance $ 21.93 $ 128.82 $ 672.75
Granted 3.99 $ 10.82 $ 98.75
Vested and released   114.55 698.25
Vested 64.80    
Forfeited 14.67 $ 101.79 $ 497.75
Ending balance $ 11.06 $ 21.93 $ 128.82