Summary of significant accounting policies (Schedule of Changes in Carrying Amount of Goodwill) (Details)	9 Months Ended
Sep. 30, 2021 USD ($)
Accounting Policies [Abstract]
Balance as of December 31, 2020	$ 8,024,729
Changes in currency translation	(418,658)
Balance as of September 30, 2021	$ 7,606,071

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(10)(1))
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
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-Name Accounting Standards Codification
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant