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

Stock Based Compensation - Company utilized Black-Scholes pricing model (Details)

v3.21.2
Stock Based Compensation - Company utilized Black-Scholes pricing model (Details) - Evolv Technologies Holdings Inc [Member]
$ in Thousands
 3 Months Ended 12 Months Ended
Mar. 31, 2021
USD ($)
Vote
shares
Mar. 31, 2020
USD ($)
shares
Dec. 31, 2020
USD ($)
shares
Dec. 31, 2019
USD ($)
shares
Fair Value Measurement Inputs and Valuation Techniques [Line Items]        
Common stock warrant liability $ 737   $ 1  
Shares Issuable Upon Exercise of Warrant | shares 5,127,237 740,991 5,127,237 3,386,246
Aggregate intrinsic value of warrants exercisable $ 800      
Number of warrants unvested | shares 6,478,316      
Intrinsic value of warrants unvested $ 18,800      
Stock compensation expense 1,082 $ 62 $ 662 $ 264
Sales and marketing        
Fair Value Measurement Inputs and Valuation Techniques [Line Items]        
Stock compensation expense 933 $ 21 $ 104 $ 170
Finback Evolv Ii Llc [Member]        
Fair Value Measurement Inputs and Valuation Techniques [Line Items]        
Common stock warrant liability $ 19,600      
Shares Issuable Upon Exercise of Warrant | shares 278,337      
Finback Evolv Ii Llc [Member] | Sales and marketing        
Fair Value Measurement Inputs and Valuation Techniques [Line Items]        
Stock compensation expense $ 800      
Risk-free interest rate        
Fair Value Measurement Inputs and Valuation Techniques [Line Items]        
Measurement input | Vote 0.40      
Expected term (in years)        
Fair Value Measurement Inputs and Valuation Techniques [Line Items]        
Measurement input | Vote 3.00      
Expected volatility        
Fair Value Measurement Inputs and Valuation Techniques [Line Items]        
Measurement input | Vote 23.90      
Expected dividend yield        
Fair Value Measurement Inputs and Valuation Techniques [Line Items]        
Measurement input | Vote 0.00