Net Loss Per Share of Common Stock - Computation of basic and diluted earnings per share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021
Earnings Per Share [Abstract]
Net loss - basic and diluted	$ (19,471)	$ (18,019)	$ (25,952)	$ (7,077)	$ (37,490)	$ (33,029)
Shares used in calculating net loss per common share - basic (in shares)	215,862,977		195,572,189		210,806,330	190,960,775
Shares used in calculating net loss per common share - diluted (in shares)	215,862,977		195,572,189		210,806,330	190,960,775
Net loss per share of common stock - basic (in USD per share)	$ (0.09)		$ (0.13)		$ (0.18)	$ (0.17)
Net loss per share of common stock - diluted (in USD per share)	$ (0.09)		$ (0.13)		$ (0.18)	$ (0.17)