3. Accounts Receivable, Net (Details) - USD ($)	Mar. 31, 2020	Dec. 31, 2019
Credit Loss [Abstract]
Accounts receivable, gross	$ 2,722,572	$ 2,557,326
Less: Allowance for doubtful accounts	(1,055,236)	(1,073,743)
Accounts receivable, net	$ 1,667,336	$ 1,483,583