Revenue from contracts with customers (Schedule of Revenues by Geography) (Details) - USD ($)	3 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Disaggregation of Revenue [Line Items]
Total revenue	$ 829,716	$ 616,933
Domestic [Member]
Disaggregation of Revenue [Line Items]
Total revenue	344,008	590,449
International [Member]
Disaggregation of Revenue [Line Items]
Total revenue	$ 485,708	$ 26,484

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

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+ Details