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 ($)
Mar. 31, 2021
Dec. 31, 2020
Sep. 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 $ 136,691,000 $ 140,774,000          
Additional paid-in capital 20,994,000 16,912,000          
Accumulated deficit (15,994,000) (11,912,000)          
Stockholders? deficit 5,000,000 5,000,000   $ 23,000 $ 0    
As previously reported              
Error Corrections and Prior Period Adjustments Restatement [Line Items]              
Additional paid-in capital   5,951,000 $ 5,121,000        
Accumulated deficit   (951,000) $ (2,000)        
Evolv Technologies Holdings Inc [Member]              
Error Corrections and Prior Period Adjustments Restatement [Line Items]              
Carrying Value 75,877,000 75,877,000   75,877,000   $ 72,883,000 $ 43,441,000
Additional paid-in capital 10,703,000 9,169,000       7,956,000  
Accumulated deficit (107,636,000) (93,881,000)       (66,489,000)  
Stockholders? deficit $ (96,903,000) (84,686,000)   $ (64,766,000)   (58,510,000) $ (38,464,000)
Evolv Technologies Holdings Inc [Member] | 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 [Member] | 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)