Annual report pursuant to Section 13 and 15(d)

Intangible assets other than goodwill - Narrative (Details)

v3.19.1
Intangible assets other than goodwill - Narrative (Details) - USD ($)
 12 Months Ended
May 18, 2017
Dec. 31, 2018
Dec. 31, 2017
Acquired Finite-Lived Intangible Assets [Line Items]      
Amortization expense   $ 112,359 $ 99,310
Net credit to cost of sales related to the amortization of contract related assets and liabilities   860,858 526,719
Fair Value, Benchmark Level of Margin Contribution, Percent 35.00%    
Intangible assets, net   2,893,990 2,896,458
Product Certifications      
Acquired Finite-Lived Intangible Assets [Line Items]      
Capitalized finited lived intangible assets   120,455 61,053
Intangible assets, net   380,501 320,363
Patents      
Acquired Finite-Lived Intangible Assets [Line Items]      
Capitalized finited lived intangible assets   102,245 181,637
Intangible assets, net   $ 722,330 653,351
Patents | Minimum      
Acquired Finite-Lived Intangible Assets [Line Items]      
Finited lived intangible assets, estimated useful life   7 years  
Patents | Maximum      
Acquired Finite-Lived Intangible Assets [Line Items]      
Finited lived intangible assets, estimated useful life   10 years  
Trademarks      
Acquired Finite-Lived Intangible Assets [Line Items]      
Capitalized finited lived intangible assets   $ 3,212 2,375
Intangible assets, net   22,752 19,540
In process R&D      
Acquired Finite-Lived Intangible Assets [Line Items]      
Intangible assets, net   263,936 263,001
Ultratek | In process R&D      
Acquired Finite-Lived Intangible Assets [Line Items]      
Intangible assets, net   $ 935 $ 263,001