XML 32 R60.htm IDEA: XBRL DOCUMENT v3.20.1
Notes payable (Details) - USD ($)
12 Months Ended
Dec. 31, 2018
Dec. 31, 2019
Notes payable (Details) [Line Items]    
Notes payable  
Bank acceptance notes from bank $ 3,642,616  
Restricted Cash, Current 3,642,616
Bank of Cangzhou [Member]    
Notes payable (Details) [Line Items]    
Bank acceptance notes from bank $ 3,642,616  
Description of maturity of notes payable The bank acceptance notes from the bank bore interest rate at nil% per annum and 0.05% of notes amount as handling charge. The acceptance notes were due and paid off in January 2019.  
Handling charges of bank acceptance notes percentage 0.05%