Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Revenue:
Total revenue	$ 46	$ 38
Costs and expenses:
Cost of goods sold		4
Research and development	1,841	2,786
Selling, general and administrative	1,177	1,857
Total costs and expenses	3,018	4,647
Operating loss	(2,972)	(4,609)
Other income (expense):
Interest income	4	16
Other expense	(1)	(1)
Total other income (expense), net	3	15
Net loss	$ (2,969)	$ (4,594)
Net loss per share, basic and diluted (in dollars per share)	$ (0.18)	$ (0.67)
Weighted-average shares used in computing net loss per share, basic and diluted (in shares)	16,569,268	6,831,976
Product [Member]
Revenue:
Total revenue		$ 5
Collaboration Agreement [Member]
Revenue:
Total revenue	$ 46	$ 33