Computation of Diluted Net Loss Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Schedule Of Computation Of Basic And Diluted Earnings Per Common Share [Line Items]
Net loss	$ (13,294)	$ (13,900)
Preferred stock dividends	(263)	(1,147)
Warrant modification	(6,622)
Net loss applicable to common stockholders	$ (20,179)	$ (15,047)
Basic and diluted net loss per share	$ (0.39)	$ (0.38)
Shares used in computing basic and diluted net loss per share	52,238	39,414