Commitments and contingencies (Details) - USD ($)		12 Months Ended
	Feb. 01, 2020	Dec. 31, 2022	Dec. 31, 2021
Commitments and contingencies
Lease term	4 years
Operating leases:
Operating lease cost		$ 396,570	$ 383,558
Variable lease cost		111,617	108,071
Operating lease expense		508,187	491,629
Lease income - sub lease		(402,486)	(424,759)
Net rent expense		105,701	66,870
Operating cash flows - operating leases		$ 406,506	368,050
Right-of-use assets obtained in exchange for operating lease liabilities			$ 122,809
Weighted-average remaining lease term - operating leases		1 year	1 year 10 months 24 days
Weighted-average discount rate - operating leases		14.70%	14.10%