Basis of Presentation - Reconciliation of Cash and Cash Equivalents to Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents (Details) - USD ($)	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Cash and cash equivalents	$ 2,722,357	$ 4,800,554	$ 3,226,451	$ 4,120,738
Merchant reserves	14,782,305	14,977,468	14,952,520	15,803,641
Total	$ 17,504,662	$ 19,778,022	$ 18,178,971	$ 19,924,379