Calculations for Basic Net Loss Per Common Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Numerator:
Net loss	$ (999)	$ (1,465)
Less: accretion of Series B convertible preferred stock dividends	(298)	(284)
Net loss available to common stockholders	$ (1,297)	$ (1,749)
Denominator:
Weighted average common shares outstanding - basic	22,574	18,443
Net loss per common share - basic	$ (0.06)	$ (0.09)