Income taxes - Future Tax Asset (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Net operating loss carry forward	$ 20,556,758	$ 20,303,013
Net Operating Loss utilized - Discontinued operations		(2,775,870)
Net operating loss utilized - continuing operations	(73,007)
Foreign exchange differential	(68,925)
Net taxable loss	3,608,654	3,029,615
Valuation allowance	(24,023,480)	(20,556,758)
Net future tax asset	$ 0	$ 0