Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Operating expenses:
Research and development	$ 6,015,616	$ 8,761,095	$ 19,433,721	$ 28,551,246
General and administrative	3,414,795	3,473,210	10,183,953	10,036,564
Total operating expenses	9,430,411	12,234,305	29,617,674	38,587,810
Other income (expense):
Interest (expense) income, net	(33)	(9,212)	(1,678)	217,908
Foreign currency (loss) gain	(21,907)	(74,565)	247,233	283,636
Total other (expense) income	(21,940)	(83,777)	245,555	501,544
Net loss	(9,452,351)	(12,318,082)	(29,372,119)	(38,086,266)
Other comprehensive loss:
Foreign currency translation	(207,608)	(168,982)	(417,438)	(836,852)
Total comprehensive loss	$ (9,659,959)	$ (12,487,064)	$ (29,789,557)	$ (38,923,118)
Net loss per share attributable to common stockholders, basic (in dollars per share)	$ (0.45)	$ (0.58)	$ (1.39)	$ (1.80)
Net loss per share attributable to common stockholders, diluted (in dollars per share)	$ (0.45)	$ (0.58)	$ (1.39)	$ (1.80)
Weighted-average common shares outstanding, basic (in shares)	21,231,584	21,186,827	21,201,910	21,115,797
Weighted-average common shares outstanding, diluted (in shares)	21,231,584	21,186,827	21,201,910	21,115,797