Earnings (Loss) per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Basic and diluted loss per share
Net loss for the period	$ (22,269)	$ (14,000)	$ (52,094)	$ (39,703)
Weighted average number of shares outstanding	28,147,226	21,276,610	27,517,267	21,236,260
Basic and diluted loss per share	$ (0.79)	$ (0.66)	$ (1.89)	$ (1.87)
Antidilutive share options
Stock option awards	3,294,240	1,969,810	3,294,240	1,969,810