Evolv Technologies Holdings, Inc. General form of registration statement for all companies including face-amount certificate companies

Stock Based Compensation - Stock based compensation expenses (Details) - Evolv Technologies Holdings Inc [Member] - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	$ 1,082	$ 62	$ 662	$ 264
Cost of revenue
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	5	2	10	2
Sales and marketing
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	933	21	104	170
General and administrative
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	94	19	370	74
Research and development
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total stock-based compensation expense	$ 50	$ 20	$ 178	$ 18