Income taxes (Tables)

12 Months Ended

Dec. 31, 2016

Income taxes

Schedule of components of the Company's income (loss) before provision for income taxes by jurisdiction

	Year ended December 31,
	2016		2015		2014
United States	$	6,013,718	$	4,431,779	$	2,563,036
Outside United States		3,628,628		1,960,309		1,397,812
Income before (benefit) provision for income taxes, net	$	9,642,346	$	6,392,088	$	3,960,848

Schedule of components of the provision for income taxes

	Year ended December 31,
	2016		2015		2014
Current tax:
United States—Federal	$	—	$	—	$	—
United States—State and local		18,588		24,456		9,456
Outside United States		1,018,649		1,484,002		756,752
Total current tax		1,037,237		1,508,458		766,208
Deferred tax:
United States—Federal		(15,648,541)		(5,840,470)		—
United States—State and local		(657,779)		(352,782)		—
Outside United States		(160,573)		714,434		34,255
Total deferred tax		(16,466,893)		(5,478,818)		34,255
(Benefit) provision for income taxes, net	$	(15,429,656)	$	(3,970,360)	$	800,463

Schedule of reconciliation from the U.S. Federal statutory income rate of 34.0% to the effective income tax rate

	Year ended December 31,
	2016		2015		2014
Federal statutory rate	34.00	%	34.00	%	34.00	%
State tax	0.19		0.38		0.24
Permanent differences	0.68		0.42		2.49
Foreign tax rates at rates different from U.S. rates	(2.67)		(11.90)		(22.06)
Valuation allowance	(190.25)		(85.02)		6.05
Total tax (benefit) provision	(158.05)	%	(62.12)	%	20.72	%

Schedule of components of deferred tax assets and liabilities

	December 31,
	2016		2015
Deferred tax assets:
Net operating loss carryforwards	$	21,030,069	$	22,842,817
Stock options		1,580,016		3,458,886
Bonuses and salaries		22,825		26,988
Restricted stock		151,358		247,620
Provision for doubtful accounts		46,607		10,987
Foreign tax credit		1,028,169		589,188
Total deferred tax assets		23,859,044		27,176,486
Less: Valuation allowance		(928,701)		(20,561,516)
Net deferred tax assets		22,930,343		6,614,970
Deferred tax liabilities:
Depreciation and amortization		(257,137)		(408,657)
Total deferred tax liabilities		(257,137)		(408,657)
Total deferred tax assets, net	$	22,673,206	$	6,206,313