Annual report pursuant to Section 13 and 15(d)

Income taxes - Narrative (Details)

v3.20.4
Income taxes - Narrative (Details) - USD ($)
12 Months Ended
Jan. 11, 2021
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2017
Feb. 05, 2021
Feb. 02, 2021
Apr. 17, 2020
PPP Loan Program | Webster Business Credit Corporation              
Operating Loss Carryforwards [Line Items]              
Notes payable             $ 1,874,200
PPP Loan Program | Webster Business Credit Corporation | Subsequent Event              
Operating Loss Carryforwards [Line Items]              
Notes payable         $ 1,874,269 $ 1,874,269  
Debt forgiveness, principal amount $ 1,874,200            
Debt forgiveness, amount 1,886,933            
Debt forgiveness, accrued interest $ 12,733            
Internal Revenue Service (IRS)              
Operating Loss Carryforwards [Line Items]              
Operating loss carryforwards   $ 37,638,000          
NOLs which expire   27,640,000          
NOLs with indefinite carryforward   9,998,000          
State Jurisdiction              
Operating Loss Carryforwards [Line Items]              
NOLs which expire   1,437,000          
Income Tax Provision              
Operating Loss Carryforwards [Line Items]              
Change in valuation allowance   1,049,000 $ 1,479,000        
American DG Energy              
Operating Loss Carryforwards [Line Items]              
Ownership interest (percent)       100.00%      
Annual limitation of acquired NOL   $ 391,940          
Period of limitation on acquired NOL   20 years