Accrued expenses (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Bonus	$ 611,228	$ 710,739
Deferred revenue	881,715	688,418
Deferred incentive	1,087,591	950,000
Other	2,773,201	4,089,443
Total accrued expenses	$ 5,353,735	6,438,600
Recognition period of deferred revenue	12 months
Non-current portion of deferred revenue		600,000
Non-current portion of deferred incentive	$ 100,000	700,000
Third party referral commissions	$ 600,000	$ 1,600,000
Maximum percentage of total current liabilities	10.00%
Long-term lease and deferred income
Non-current portion of deferred revenue	$ 700,000