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

Long-term Debt - Convertible notes 2021 (Details)

v3.21.2
Long-term Debt - Convertible notes 2021 (Details) - USD ($)
1 Months Ended 2 Months Ended 3 Months Ended 6 Months Ended 12 Months Ended
Jun. 30, 2021
Jun. 21, 2021
Feb. 04, 2021
Jan. 21, 2021
Oct. 31, 2019
Mar. 31, 2020
Jun. 30, 2021
Jun. 30, 2021
Dec. 31, 2020
Dec. 31, 2019
Debt Instrument [Line Items]                    
Derivative liability recognized in the extinguishment accounting                 $ 21,519,000  
Evolv Technologies Holdings, Inc.                    
Debt Instrument [Line Items]                    
Loss on extinguishment of debt             $ (11,820,000) $ (11,820,000) $ (66,000) $ (679,000)
Evolv Technologies Holdings, Inc. | 2021 Convertible Notes                    
Debt Instrument [Line Items]                    
Gross proceeds from issuance     $ 30,000,000.0 $ 30,000,000.0            
Interest rate     8.00% 8.00%            
Additional gross proceeds made available upon achievement of the integration milestone     $ 100,000,000.0 $ 100,000,000.0            
Conversion price as percentage of the price per share paid by the other investors     80.00% 80.00%            
Embedded derivative fair value     $ 7,000,000.0 $ 7,000,000.0            
Initial carrying value $ 30,000,000 $ 29,600,000 23,000,000.0 23,000,000.0     30,000,000 30,000,000    
Total interest incurred 100,000           2,800,000 4,700,000    
Fair value of derivative liability 9,200,000           9,200,000 9,200,000    
Number of shares issued upon conversion of debt   1,000,000                
Loss on extinguishment of debt   $ 11,800,000                
Carrying value of notes derecognized   26,700,000                
Face amount of debt 30,000,000 $ 29,600,000 $ 23,000,000.0 $ 23,000,000.0     30,000,000 30,000,000    
Derivative liability recognized in the extinguishment accounting $ 19,200,000           $ 19,200,000 19,200,000    
Mark to market change, additional loss               $ 100,000    
Evolv Technologies Holdings, Inc. | Series B-1 Preferred Stock                    
Debt Instrument [Line Items]                    
Number of shares issued upon conversion of debt         18,056,296 8,486,175