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

Nature of the Business and Basis of Presentation - Impacts of Error on Condensed Financial Statements (Details)

v3.21.2
Nature of the Business and Basis of Presentation - Impacts of Error on Condensed Financial Statements (Details) - USD ($)
Jun. 30, 2021
Mar. 31, 2021
Dec. 31, 2020
Sep. 30, 2020
Jun. 30, 2020
Mar. 31, 2020
Jan. 23, 2020
Dec. 31, 2019
Dec. 31, 2018
Error Corrections and Prior Period Adjustments Restatement [Line Items]                  
Carrying Value $ 129,066,000   $ 140,774,000            
Additional paid-in capital 28,620,000   16,912,000            
Accumulated deficit (23,620,000)   (11,912,000)            
Stockholders' deficit 5,000,000 $ 5,000,000 5,000,000   $ 23,000 $ 25,000 $ 0    
As previously reported                  
Error Corrections and Prior Period Adjustments Restatement [Line Items]                  
Carrying Value               $ 72,399,000  
Additional paid-in capital     5,951,000 $ 5,121,000          
Accumulated deficit     (951,000) $ (2,000)          
Evolv Technologies Holdings, Inc.                  
Error Corrections and Prior Period Adjustments Restatement [Line Items]                  
Carrying Value 75,877,000 75,877,000 75,877,000   75,877,000 75,877,000   72,883,000 $ 43,441,000
Additional paid-in capital 11,435,000   9,169,000         7,956,000  
Accumulated deficit (130,007,000)   (93,881,000)         (66,489,000)  
Stockholders' deficit $ (118,537,000) $ (96,903,000) (84,686,000)   $ (69,807,000) $ (64,766,000)   (58,510,000) $ (38,464,000)
Evolv Technologies Holdings, Inc. | As previously reported                  
Error Corrections and Prior Period Adjustments Restatement [Line Items]                  
Carrying Value     75,393,000         72,399,000  
Additional paid-in capital     9,921,000         8,708,000  
Accumulated deficit     (94,149,000)         (66,757,000)  
Stockholders' deficit     (84,202,000)         (58,026,000)  
Evolv Technologies Holdings, Inc. | Adjustment                  
Error Corrections and Prior Period Adjustments Restatement [Line Items]                  
Carrying Value     484,000         484,000  
Additional paid-in capital     (752,000)         (752,000)  
Accumulated deficit     268,000         268,000  
Stockholders' deficit     $ (484,000)         $ (484,000)