Commitments and contingencies (Tables)

12 Months Ended

Dec. 31, 2017

Commitments and Contingencies Disclosure [Abstract]

Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]

Future minimum lease payments under these non-cancellable operating leases as of December 31, 2017 are as follows:

2018	$	613,510
2019		385,548
2020		259,289
2021		46,297
2022		-
Thereafter		-
	$	1,304,644