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Deferred Government Grants (Tables)
 9 Months Ended
Sep. 30, 2019
Deferred Government Grants [Abstract]  
Schedule of deferred government grants
   December 31,   September 30, 
   2018   2019 
Total government grants  $4,457,064   $4,184,634 
Less: Current portion   (143,775)   (138,334)
Non-current portion  $4,313,289   $4,046,300