Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Revenue:
Total revenue	$ 60	$ 46
Costs and expenses:
Research and development	2,186	1,841
Selling, general and administrative	1,201	1,177
Total costs and expenses	3,387	3,018
Operating loss	(3,327)	(2,972)
Other income (expense):
Total other income, net	2	3
Net loss	$ (3,325)	$ (2,969)
Net loss per share, basic and diluted (in dollars per share)	$ (0.19)	$ (0.18)
Weighted-average shares used in computing net loss per share, basic and diluted (in shares)	17,066,068	16,569,268
Product [Member]
Revenue:
Total revenue	$ 1	$ 0
Collaboration Agreement [Member]
Revenue:
Total revenue	$ 59	$ 46