Property and equipment (Tables)

3 Months Ended

Mar. 31, 2016

Property and equipment

Schedule of property and equipment, net

	Estimated			As of		As of
	useful life			March 31,		December 31,
	(in years)			2016		2015
Equipment	2	-	7	$	960,281	$	958,175
Computer hardware	3	-	5		3,397,404		3,266,233
Furniture and fixtures	5	-	7		203,536		192,565
Leasehold improvements	3	-	10		778,359		746,336
Total property and equipment, gross					5,339,580		5,163,309
Less: Accumulated depreciation and amortization					(3,517,603)		(3,351,690)
Property and equipment, net				$	1,821,977	$	1,811,619

Schedule of property and equipment depreciation and amortization expense

	Three Months Ended
	March 31,
	2016		2015
Depreciation and amortization expense	$	163,126	$	171,229