Segment information - Information about revenue, profit and assets (Details)	3 Months Ended		12 Months Ended
	Mar. 31, 2017 USD ($) item	Mar. 31, 2016 USD ($)	Dec. 31, 2016 USD ($)
Segment information
Number of reportable segments | item	2
Cost of sales included in processing and services costs	$ 3,192,073	$ 3,500,668
Long-lived assets	$ 6,800,000		$ 7,000,000
Number of geographical regions in which the entity conducts its business | item	3
Net Revenue:
Net revenue	$ 12,728,885	13,684,513	13,684,513
Gross Profit:
Total gross profit	7,421,203		7,492,621
Income from operations before benefit (provision) for income taxes:
Total gross profit	7,421,203		7,492,621
Selling, general and administrative expenses	5,287,338	5,480,714	5,480,714
Restructuring charges	65,458
Income from operations	2,068,407	2,011,907	2,011,907
Interest expense	(116,332)	(14,676)	(14,676)
Interest income	523	424	424
Total other expense, net	(115,809)	(14,252)	(14,252)
Income from operations before provision for income taxes	1,952,598	1,997,655	1,997,655
Operating segments
Gross Profit:
Total gross profit	10,099,478		10,252,867
Income from operations before benefit (provision) for income taxes:
Total gross profit	10,099,478		10,252,867
Corporate allocated cost of sales
Gross Profit:
Total gross profit	2,678,275		2,760,246
Income from operations before benefit (provision) for income taxes:
Total gross profit	2,678,275		2,760,246
Multi-currency processing services
Segment information
Cost of sales included in processing and services costs	500,000	$ 700,000
Net Revenue:
Net revenue	8,432,904		8,634,232
Multi-currency processing services | Operating segments
Gross Profit:
Total gross profit	7,919,106		7,893,810
Income from operations before benefit (provision) for income taxes:
Total gross profit	7,919,106		7,893,810
Payment processing services
Net Revenue:
Net revenue	4,295,981		5,050,281
Payment processing services | Operating segments
Gross Profit:
Total gross profit	2,180,372		2,359,057
Income from operations before benefit (provision) for income taxes:
Total gross profit	2,180,372		2,359,057
APAC
Net Revenue:
Net revenue	4,093,385		3,817,064
APAC | Multi-currency processing services | Operating segments
Gross Profit:
Total gross profit	4,072,794		3,793,504
Income from operations before benefit (provision) for income taxes:
Total gross profit	4,072,794		3,793,504
Americas
Net Revenue:
Net revenue	2,969,152		2,185,374
Americas | Multi-currency processing services | Operating segments
Gross Profit:
Total gross profit	2,796,896		2,034,688
Income from operations before benefit (provision) for income taxes:
Total gross profit	2,796,896		2,034,688
EMEA
Net Revenue:
Net revenue	1,370,367		2,631,794
EMEA | Multi-currency processing services | Operating segments
Gross Profit:
Total gross profit	1,049,416		2,065,618
Income from operations before benefit (provision) for income taxes:
Total gross profit	$ 1,049,416		$ 2,065,618