Basis of Presentation - Reconciliation of Cash and Cash Equivalents to Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents (Details) - USD ($)	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Cash and cash equivalents	$ 2,716,316	$ 4,800,554	$ 2,199,849	$ 4,120,738
Merchant reserves	13,602,562	14,977,468	14,908,900	15,803,641
Total	$ 16,318,878	$ 19,778,022	$ 17,108,749	$ 19,924,379