Balance Sheet Components (Schedule Of Accrued Expenses) (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Balance Sheet Components [Abstract]
Compensation expense	$ 1,172	$ 1,699
Accrued clinical	512	262
Professional fees	37	51
Property and equipment	234	234
Other	116	250
Accrued expenses	$ 2,071	$ 2,496