Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Revenue
Grant revenue		$ 1,699,000
Type of Revenue [Extensible List]	us-gaap:GrantMember	us-gaap:GrantMember
Operating expenses
Research and development	$ 3,491,000	$ 2,848,000
General and administrative	3,951,000	4,590,000
Loss on impairment of long-lived assets	2,870,000
Total operating expenses	10,312,000	7,438,000
Loss from operations	(10,312,000)	(5,739,000)
Interest income	217,000	346,000
Other (expense) income, net	(701,000)	689,000
Net loss	$ (10,796,000)	$ (4,704,000)
Net loss per share - basic and diluted	$ (0.72)	$ (0.42)
Weighted-average common shares used to compute basic and diluted net loss per share	15,013	11,273