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

Warrants - fair value of warrants (Details)

v3.21.2
Warrants - fair value of warrants (Details) - USD ($)
3 Months Ended 6 Months Ended 11 Months Ended 12 Months Ended
Jun. 30, 2021
Jun. 30, 2020
Jun. 30, 2021
Jun. 30, 2020
Dec. 31, 2020
Dec. 31, 2020
Dec. 31, 2019
Class of Warrant or Right [Line Items]              
Changes in the fair value of warrants $ 959,000   $ 3,605,000   $ 10,571,000    
Evolv Technologies Holdings, Inc.              
Class of Warrant or Right [Line Items]              
Changes in the fair value of warrants $ 185,000 $ 0 $ 921,000 $ 0      
Evolv Technologies Holdings, Inc. | Maximum              
Class of Warrant or Right [Line Items]              
Changes in the fair value of warrants           $ 100,000 $ 100,000