Condensed Consolidated Statements Of Operations And Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Operating expenses:
General and administrative	$ 5,771	$ 5,606	$ 16,691	$ 15,153
Research and development	6,968	6,192	19,019	18,371
Amortization of intangible assets	166	166	499	500
Total operating expenses	12,905	11,964	36,209	34,024
Other income:
Interest income	9	218	108	841
Total other income	9	218	108	841
Net loss	(12,896)	(11,746)	(36,101)	(33,183)
Other comprehensive loss:
Unrealized gain (loss) on available-for-sale securities	1	(14)	(3)	9
Comprehensive loss	$ (12,895)	$ (11,760)	$ (36,104)	$ (33,174)
Net loss per share:
Basic and diluted net loss per share	$ (0.51)	$ (0.57)	$ (1.60)	$ (1.60)
Weighted average shares used to compute net loss per common share - basic and diluted	25,223	20,774	22,540	20,728