Note 4 - Accounts Receivable - Accounts Receivable (Details) - USD ($)	Jun. 30, 2019	Dec. 31, 2018
Accounts receivable	$ 1,715,033	$ 39,769
Provision for doubtful accounts	(52,904)	(27,666)
Net accounts receivable	$ 1,662,129	$ 12,103