XML 16 R5.htm IDEA: XBRL DOCUMENT v3.21.1
CONSOLIDATED STATEMENTS OF INCOME (Parenthetical) - USD ($)
3 Months Ended
Mar. 31, 2021
Mar. 31, 2020
Cost of revenue.    
Purchases from related parties $ 155,982 $ 493,463
General and administrative expense]    
Purchases from related parties $ 4,429