Condensed Consolidated Statements of Operations and Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Operating expenses:
Research and development	$ 4,218	$ 4,182	$ 12,817	$ 12,191
General and administrative	2,298	2,142	7,761	6,920
Total operating expenses	6,516	6,324	20,578	19,111
Loss from operations	(6,516)	(6,324)	(20,578)	(19,111)
Other (expense) income, net:
Interest expense	(276)	(2)	(823)	(2)
Interest income	81	324	423	1,097
Other income (expense), net	114	(12)	83	(17)
Total other (expense) income, net	(81)	310	(317)	1,078
Net loss	(6,597)	(6,014)	(20,895)	(18,033)
Other comprehensive (loss) income, net:
Unrealized (loss) gain on available-for-sale securities, net	(71)	(14)	(2)	69
Foreign currency translation (loss) gain	(56)	7	(48)	6
Total other comprehensive (loss) income, net	(127)	(7)	(50)	75
Comprehensive loss	$ (6,724)	$ (6,021)	$ (20,945)	$ (17,958)
Net loss per share, basic and diluted	$ (0.31)	$ (0.35)	$ (1.11)	$ (1.04)
Weighted-average common shares outstanding, basic and diluted	21,374,240	17,376,236	18,885,623	17,376,236