Taxation (Details 1) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Schedule Of Taxation [Line Items]
Income before tax	$ 15,536,515	$ 21,529,221
Provision for income taxes at PRC statutory income tax rate (25%)	3,884,129	5,382,305
Impact of different tax rates in other jurisdictions	144,866	(75,504)
Effect of PRC preferential tax rate	(1,587,956)	(2,313,343)
R&D expenses eligible for super deduction	(776,444)	(451,003)
Other non-deductible expenses	139,090	754,820
Toll-charge from the Tax Act	0	5,773,436
Foreign tax credits	0	(2,063,810)
Change in valuation allowance of deferred tax assets	578,249	(2,691,576)
Total income taxes expenses	$ 2,381,934	$ 4,315,325