Net Loss per Share - Basic and diluted net loss per share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Earnings Per Share [Abstract]
Net loss attributable to common shareholders	$ (6,993)	$ (6,997)	$ (18,802)	$ (25,779)
Weighted average common shares outstanding (in shares)	53,908,520	51,910,517	53,670,652	50,777,222
Net loss per share, basic and diluted (in dollars per share)	$ (0.13)	$ (0.13)	$ (0.35)	$ (0.51)
Comprehensive loss	$ (6,993)	$ (6,997)	$ (18,802)	$ (25,779)