Loss per share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share [Abstract]
Net loss	$ (17,701)	$ (6,376)	$ (39,255)	$ (20,045)
Basic weighted average number of common stock outstanding (in shares)	67,232,000	32,099,000	67,227,000	31,632,000
Diluted weighted average number of common stock outstanding (in shares)	67,232,000	32,099,000	67,227,000	31,632,000
Basic (loss) / earnings per common stock from operations (in dollars per share)	$ (0.26)	$ (0.20)	$ (0.58)	$ (0.63)
Diluted (loss) / earnings per common stock from operations (in dollars per share)	$ (0.26)	$ (0.20)	$ (0.58)	$ (0.63)
Anti-dilutive shares excluded from diluted earnings per share (in shares)			11,974,480	4,131,511