Condensed Consolidated Statements Of Operations And Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Condensed Consolidated Statements Of Operations And Comprehensive Loss [Abstract]
Revenue
Operating expenses:
General and administrative	5,603	4,401
Research and development	6,181	5,842
Amortization of intangible assets	166	167
Total operating expenses	11,950	10,410
Other income:
Interest income	78	332
Total other income	78	332
Net loss	(11,872)	(10,078)
Other comprehensive loss:
Unrealized gain on available-for-sale securities	13	3
Comprehensive loss	$ (11,859)	$ (10,075)
Net loss per share:
Basic and diluted net loss per share	$ (0.57)	$ (0.49)
Weighted average shares used to compute net loss per common share - basic and diluted	20,838	20,679