Earnings (Loss) per Share - Basic and Diluted (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020
Basic and diluted loss per share
Net loss for the period	$ (11,754)	$ (13,981)	$ (15,441)	$ (23,259)	$ (25,735)	$ (38,700)
Weighted average number of shares outstanding, Basic	40,573,848		11,277,825		33,532,837	10,368,670
Weighted average number of shares outstanding, Diluted	40,573,848		11,277,825		33,532,837	10,368,670
Basic (in dollars per share)	$ (0.29)		$ (1.37)		$ (0.77)	$ (3.73)
Diluted (in dollars per share)	$ (0.29)		$ (1.37)		$ (0.77)	$ (3.73)