Accounts receivable, net

12 Months Ended

Dec. 31, 2017

Receivables [Abstract]

Loans, Notes, Trade and Other Receivables Disclosure [Text Block]

4. Accounts receivable, net

	December 31,
	2017		2016
Trade accounts receivable	$	13,609,203	$	15,368,218
Receivable from OC-BVI		123,807		53,970
Other accounts receivable		1,473,738		1,271,948
		15,206,748		16,694,136
Allowance for doubtful accounts		(158,902)		(193,338)
Accounts receivable, net	$	15,047,846	$	16,500,798

The activity for the allowance for doubtful accounts consisted of:

	December 31,
	2017		2016
Opening allowance for doubtful accounts	$	193,338	$	193,338
Provision for doubtful accounts		-		42,553
Accounts written off during the year		(34,436)		(42,553)
Ending allowance for doubtful accounts	$	158,902	$	193,338

Significant concentrations of credit risk are disclosed in Note 20.