Deferred revenue (Tables)

12 Months Ended

Dec. 31, 2017

Statement [Line Items]

Disclosure of changes in deferred revenue [Table Text Block]

Balance, January 1, 2016	$	597,260
Recognition of revenue		(65,762	)
Effects of changes in foreign exchange		6,354
Balance, December 31, 2016	$	537,852
Recognition of revenue		(48,958	)
Effects of changes in foreign exchange		9,150
Balance, December 31, 2017	$	498,044

Disclosure of detailed information about deferred revenue [Table Text Block]

		Dec. 31, 2017		Dec. 31, 2016
Current	$	49,907	$	65,619
Non-current		448,137		472,233
	$	498,044	$	537,852