Quarterly report pursuant to Section 13 or 15(d)

Cover

v3.21.1
Cover - shares
 3 Months Ended
Mar. 31, 2021
May 03, 2021
Document and Entity Information [Abstract]    
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Mar. 31, 2021  
Document Transition Report false  
Entity File Number 001-36103  
Entity Registrant Name TECOGEN INC.  
Entity Incorporation, State or Country Code DE  
Entity Tax Identification Number 04-3536131  
Entity Address, Address Line One 45 First Avenue  
Entity Address, City or Town Waltham  
Entity Address, State or Province MA  
Entity Address, Postal Zip Code 02451  
City Area Code 781  
Local Phone Number 466-6402  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Non-accelerated Filer  
Entity Small Business true  
Entity Emerging Growth Company false  
Entity Shell Company false  
Entity Common Stock, Shares Outstanding   24,850,261
Entity Central Index Key 0001537435  
Current Fiscal Year End Date --12-31  
Document Fiscal Year Focus 2021  
Document Fiscal Period Focus Q1  
Amendment Flag false