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

Long-term Debt - Term loan (Details)

v3.21.2
Long-term Debt - Term loan (Details)
 1 Months Ended 6 Months Ended 12 Months Ended
Jul. 05, 2017
USD ($)
item
Dec. 31, 2020
USD ($)
$ / shares
shares
Mar. 31, 2020
USD ($)
item
$ / shares
shares
Jun. 30, 2021
USD ($)
M
$ / shares
shares
Dec. 31, 2020
USD ($)
$ / shares
shares
Dec. 31, 2019
USD ($)
shares
Feb. 12, 2019
$ / shares
shares
Debt Instrument [Line Items]              
Warrants to purchase shares of common stock | shares           3,386,246  
Evolv Technologies Holdings, Inc.              
Debt Instrument [Line Items]              
Number of monthly payments 36     36      
Warrants to purchase shares of common stock | shares   5,127,237 740,991 5,127,237 5,127,237    
Warrants exercise price | $ / shares     $ 0.15        
Fair value of warrants     $ 100,000        
Debt issuances costs     100,000        
End-of-term charge     100,000        
Evolv Technologies Holdings, Inc. | 2020 SVB Term Loan              
Debt Instrument [Line Items]              
Face amount of debt   $ 5,000,000.0 5,000,000.0   $ 5,000,000.0    
Repayments of debt   8,000,000.0 $ 3,100,000        
Number of monthly payments | item     36        
Interest rate       5.00%      
Warrants to purchase shares of common stock | shares       740,991      
Warrants exercise price | $ / shares       $ 0.15      
Fair value of warrants       $ 100,000      
Debt issuances costs       100,000      
End-of-term charge       $ 100,000      
Interest expense         100,000    
Evolv Technologies Holdings, Inc. | Revolving line of credit outstanding              
Debt Instrument [Line Items]              
Face amount of debt $ 1,000,000.0 10,000,000.0 $ 7,000,000.0   10,000,000.0    
Maximum borrowing capacity 1,000,000.0 $ 10,000,000.0 7,000,000.0   10,000,000.0    
Repayments of debt         $ 3,000,000.0    
Interest rate   4.50%     4.50%    
Evolv Technologies Holdings, Inc. | 2017 SVB Term Loan              
Debt Instrument [Line Items]              
Face amount of debt $ 5,000,000.0   $ 3,100,000        
Number of monthly payments | item 36            
Interest rate           5.25%  
Warrants to purchase shares of common stock | shares             75,000
Warrants exercise price | $ / shares             $ 0.09
Interest expense           $ 200,000  
Evolv Technologies Holdings, Inc. | Wall Street Journal Prime Rate              
Debt Instrument [Line Items]              
Warrants to purchase shares of common stock | shares   1,000,000     1,000,000    
Warrants exercise price | $ / shares   $ 0.16     $ 0.16    
Fair value of warrants   $ 100,000     $ 100,000    
Debt issuances costs         $ 200,000    
Evolv Technologies Holdings, Inc. | Wall Street Journal Prime Rate | 2020 SVB Term Loan              
Debt Instrument [Line Items]              
Spread on variable rate     0.50%        
Interest rate     5.00% 0.50%      
Evolv Technologies Holdings, Inc. | Wall Street Journal Prime Rate | Revolving line of credit outstanding              
Debt Instrument [Line Items]              
Spread on variable rate         1.25%    
Interest rate   4.50%     4.50%    
Evolv Technologies Holdings, Inc. | Wall Street Journal Prime Rate | 2017 SVB Term Loan              
Debt Instrument [Line Items]              
Spread on variable rate 1.25%            
Interest rate 1.25%           5.25%