Net (loss) income per common share - Basic and Diluted Earnings (Details) - USD ($)	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Basic earnings per share
Net loss per share from continuing operations, amount	$ (8,076,411)	$ (8,190,376)	$ (996,696)
Net loss per share from continuing operations, number of shares	123,852,105	107,352,184	48,305,978
Net loss per share from continuing operations, per share	$ (0.07)	$ (0.08)	$ (0.02)
Net income per share from discontinued operations, amount		$ 6,821,889	$ 735,987
Net income per share from discontinued operations, number of shares	123,852,105	107,352,184	48,305,978
Net loss	$ (8,178,643)	$ (1,368,487)	$ (260,709)
Diluted earnings per share
Net loss per share from continuing operations, amount	$ (8,178,643)	$ (8,190,376)	$ (996,696)
Net loss per share from continuing operations, per share	$ (0.07)	$ (0.06)	$ (0.02)
Net income per share from discontinued operations, amount		$ 6,821,889	$ 735,987
Net income per share from discontinued operations, number of shares	123,852,105	148,801,780
Net income per share from discontinued operations, per share	$ (0.07)	$ (0.01)
Net Income Per Share
Basic earnings per share
Net loss per share from continuing operations, amount		$ (8,190,376)
Net loss per share from continuing operations, number of shares		107,352,184
Net loss per share from continuing operations, per share		$ (0.08)
Net income per share from discontinued operations, amount		$ 6,821,889
Net income per share from discontinued operations, number of shares		107,352,184
Net income per share from discontinued operations, per share		$ 0.06
Net loss		$ 4,285,993
Diluted earnings per share
Net loss per share from continuing operations, amount		$ (8,190,376)
Net loss per share from continuing operations, number of shares		148,801,780
Net loss per share from continuing operations, per share		$ (0.06)
Net income per share from discontinued operations, amount		$ 6,821,889
Net income per share from discontinued operations, number of shares		148,801,780
Net income per share from discontinued operations, per share		$ 0.05

Represents net loss before taxation from continuing operations.

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