Accrued expenses (Details) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Bonus	$ 34,846	$ 611,228
Deferred revenue	821,447	881,715
Deferred incentive	699,798	1,087,591
Other	3,660,364	2,773,201
Total accrued expenses	$ 5,216,455	5,353,735
Recognition period of deferred revenue	12 months
Third party referral commissions	$ 800,000	$ 600,000
Maximum percentage of total current liabilities	10.00%	10.00%
Other long-term liabilities
Non-current portion of deferred revenue	$ 500,000	$ 700,000
Non-current portion of deferred incentive		$ 100,000