Annual report pursuant to Section 13 and 15(d)

Document and Entity Information

Document and Entity Information - USD ($)
12 Months Ended
Dec. 31, 2019
Mar. 23, 2020
Jun. 28, 2019
Document and Entity Information [Abstract]      
Entity Registrant Name SG BLOCKS, INC.    
Entity Central Index Key 0001023994    
Trading Symbol SGBX    
Amendment Flag false    
Current Fiscal Year End Date --12-31    
Document Type 10-K    
Document Annual Report true    
Document Transition Report false    
Document Period End Date Dec. 31, 2019    
Document Fiscal Period Focus FY    
Document Fiscal Year Focus 2020    
Entity Filer Category Non-accelerated Filer    
Entity Incorporation, State or Country Code DE    
Entity Address, State or Province NY    
Entity Address, Address Line One 195 Montague Street,    
Entity Address, Address Line Two 14th Floor,    
Entity Address, City or Town Brooklyn    
Entity Address, Postal Zip Code 11201    
City Area Code (646)    
Local Phone Number 240-4235    
Title of 12(b) Security Common Stock, par value $0.01 per share    
Security Exchange Name NASDAQ    
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
Entity Interactive Data Current Yes    
Entity Current Reporting Status Yes    
Entity File Number 001-38037    
Entity Tax Identification Number 95-4463937    
Entity Shell Company false    
Entity Small Business true    
Entity Emerging Growth Company false    
Entity Public Float     $ 3,597,728
Entity Common Stock, Shares Outstanding   1,170,524