CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Operating expenses:
Research and development	$ 10,239	$ 10,677	$ 21,862	$ 21,679
General and administrative	3,241	3,421	7,021	6,609
Total operating expenses	13,480	14,098	28,883	28,288
Loss from operations	(13,480)	(14,098)	(28,883)	(28,288)
Other income:
Grant income	48	372	62	1,201
Interest income	36	417	159	908
Total other income	84	789	221	2,109
Loss before income taxes	(13,396)	(13,309)	(28,662)	(26,179)
Provision for income taxes		73		144
Net loss	$ (13,396)	$ (13,382)	$ (28,662)	$ (26,323)
Net Loss per Share
Net loss per share-basic and diluted (in dollar per share)	$ (0.78)	$ (1.02)	$ (1.89)	$ (2.00)
Weighted average common stock outstanding-basic and diluted (in shares)	17,095,140	13,131,291	15,193,351	13,128,956
Other comprehensive loss:
Net loss	$ (13,396)	$ (13,382)	$ (28,662)	$ (26,323)
Net unrealized gain (loss) on investments held	(28)	20		63
Comprehensive loss	$ (13,424)	$ (13,362)	$ (28,662)	$ (26,260)