Cash and cash equivalents (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Cash and Cash Equivalents [Line Items]
Bank accounts	$ 34,518,257	$ 28,708,434
Short term deposits	9,275,893	13,362,649
Cash and cash equivalents at end of period	43,794,150	42,071,083
United States dollar [Member]
Cash and Cash Equivalents [Line Items]
Bank accounts	14,001,264	15,661,140
Short term deposits	5,796,582	11,100,185
Cayman Islands dollar [Member]
Cash and Cash Equivalents [Line Items]
Bank accounts	5,650,874	6,690,274
Short term deposits	2,413,547	1,209,954
Bahamian dollar [Member]
Cash and Cash Equivalents [Line Items]
Bank accounts	14,863,287	6,353,936
Short term deposits	1,065,764	1,052,510
Bermudian dollar [Member]
Cash and Cash Equivalents [Line Items]
Bank accounts	$ 2,832	$ 3,084