XML 43 R31.htm IDEA: XBRL DOCUMENT v3.19.2
Inventories (Tables)
6 Months Ended
Jun. 30, 2019
Inventories [Abstract]  
Schedule of inventories
   December 31,   June 30, 
   2018   2019 
Raw materials  $1,675,383   $973,706 
Work in progress   2,737,415    1,931,391 
Finished goods   5,209,563    5,805,211 
   $9,622,361   $8,710,308