Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Revenues
Revenues	$ 7,143	$ 1,120
Operating expenses
Research and development	64,535	71,588
General and administrative	29,972	24,998
Total operating expenses	94,507	96,586
Loss from operations	(87,364)	(95,466)
Other income (expense):
Interest income	1,351	1,639
Interest expense	(4,280)	(4,199)
Change in fair value of warrant liability	(19,192)	0
Other expense	(2,992)	(10)
Total other expense	(25,113)	(2,570)
Net loss	$ (112,477)	$ (98,036)
Net loss per common share attributable to common shareholders, basic and diluted (in usd per share)	$ (24.01)	$ (24.37)
Weighted-average shares outstanding-basic and diluted (in shares)	4,684,711	4,023,058
Net loss	$ (112,477)	$ (98,036)
Other comprehensive loss:
Unrealized gain on available-for-sale securities, net of tax	45	1
Foreign currency translation adjustment	(228)	(99)
Comprehensive loss	(112,660)	(98,134)
Grants
Revenues
Revenues	2,143	1,120
License fee revenue
Revenues
Revenues	$ 5,000	$ 0