Commitments and contingencies (Tables)

12 Months Ended

Dec. 31, 2016

Commitments and contingencies

Schedule of operating lease expense

	Year ended December 31,
	2016		2015		2014
Operating lease expense	$	1,477,382	$	1,577,764	$	1,549,343

Schedule of future minimum rental payments under non-cancelable operating leases

Years ending December 31,
2017	$	1,176,928
2018		737,115
2019		580,566
2020		82,285
2021		84,748
Thereafter		7,202
Total minimum lease payments	$	2,668,844

Schedule of leased property under capital leases

	December 31,
	2016		2015
Computer hardware	$	2,267,950	$	2,145,668
Computer software		319,500		319,683
Total capital leases, gross		2,587,450		2,465,351
Less: Accumulated depreciation		(1,824,534)		(1,415,472)
Total capital leases, net	$	762,916	$	1,049,879

Schedule of future minimum rental payment under capital leases

Years ending December 31,
2017	$	176,022
2018		83,603
2019		14,031
2020		5,244
2021		2,185
Thereafter		—
Total minimum lease payments		281,085
Less: Amounts representing taxes, included in total minimum lease payments(*)		—
Net minimum lease payments		281,085
Less: Amounts representing interest payments		(12,242)
Present value of net minimum lease payments	$	268,843

(*)Tax amounts related to capital lease payments are inconsequential.

Schedule of future minimum payments under those agreements

Years ending December 31,
2017	$	416,667
2018		300,000
2019		—
2020		—
2021		—
Thereafter		—
Total payments	$	716,667