Condensed Consolidated Statements of Operations and Comprehensive Loss (unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating expenses
Research and development	$ 3,988	$ 7,164
General and administrative	2,643	2,979
Change in fair value of contingent consideration	(858)	(987)
Total operating expenses	5,773	9,156
Operating loss	(5,773)	(9,156)
Other income
Change in fair value of warrants liabilities	27	201
Interest income	22	1
Total other income	49	202
Net loss	(5,724)	(8,954)
Other comprehensive loss
Foreign currency translation adjustment	(2)
Total comprehensive loss	$ (5,726)	$ (8,954)
Net loss per common share, basic and diluted	$ (0.07)	$ (0.11)
Weighted-average common shares outstanding used to calculate basic and diluted net loss per common share	80,020,677	79,694,781