Summary of significant accounting policies (Details) (USD $)	3 Months Ended	12 Months Ended
	Sep. 30, 2012	Dec. 31, 2013 item	Dec. 31, 2012	Dec. 31, 2011
Revenue recognition
Number of revenue streams		2
Payment processing services revenue
Provision for sales credits		$ 0	$ 0	$ 0
Translation of non-U.S. currencies
Amounts resulting from foreign currency transactions included in statement of operations		100,000
Allowance for doubtful accounts
Allowance for doubtful accounts		200,000	1,500,000
Trade receivable written-off		1,400,000
Goodwill, intangibles and long-lived assets
Amortization period of acquired identifiable intangible assets		5 years
Software development costs and amortization
Capitalized software development costs		4,904,415	4,776,320
Amortization expense		1,600,000	1,700,000	1,500,000
Deferred initial public offering ("IPO") costs
Minimum period for which initial public offering was likely to be postponed		90 days
Write-off of deferred IPO costs	2,300,000		2,346,210
Initial public offering costs	2,600,000
Due to merchants
Number of average days for which ACH funds are generally held before payment to merchant		3 days
Income taxes
Uncertain tax positions		$ 0	$ 0
Minimum
Software development costs and amortization
Estimated useful live		3 years
Maximum
Software development costs and amortization
Estimated useful live		5 years