Stock-based compensation expense (Details) - USD ($) shares in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Stock-based expense
Total stock-based compensation expense	$ 603,968	$ 233,462
Processing and service costs
Stock-based expense
Total stock-based compensation expense	48,806	50,497
Selling general and administrative expenses
Stock-based expense
Total stock-based compensation expense	555,162	$ 182,965
Stock options
Stock-based expense
Options granted (in shares)		0.8
Fair value of options granted	$ 700,000
Requisite service period	36 months
Total stock-based compensation expense	$ 281,396	$ 131,272
Restricted stock
Stock-based expense
Total stock-based compensation expense	$ 322,572	$ 102,190