UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Revenue:
Collaboration revenue	$ 2,443	$ 527	$ 16,473	$ 986
Total revenue	2,443	527	16,473	986
Operating expenses:
Research and development expense	9,139	4,245	22,222	11,073
General and administrative expense	2,424	2,228	7,227	6,421
Total operating expenses	11,563	6,473	29,449	17,494
Operating loss	(9,120)	(5,946)	(12,976)	(16,508)
Other income (expense), net:
Dividend income	2	228	45	415
Interest income	205	1	832	3
Interest expense	(27)	(203)	(155)	(589)
Other income (expense), net	118	104	271	357
Total other income (expense), net	298	130	993	186
Net loss	$ (8,822)	$ (5,816)	$ (11,983)	$ (16,322)
Basic and diluted loss per common share (in usd per share)	$ (0.10)	$ (0.09)	$ (0.14)	$ (0.32)
Weighted average basic and diluted common shares outstanding (in shares)	87,227,136	64,651,040	87,160,520	51,200,072