Earnings Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Earnings Per Share
Net loss	$ (2,070)	$ (3,556)	$ (7,706)	$ (7,222)
Less: decrease in fair value of investor warrants	(2,886)	(116)	(4,217)	(267)
Net loss available to common stockholders	$ (4,956)	$ (3,672)	$ (11,923)	$ (7,489)
Basic weighted-average common shares outstanding	226,085,867	196,179,371	226,084,605	195,785,398
Add: dilutive effect of equity instruments		5,268,667		5,199,951
Diluted weighted-average shares outstanding	226,085,867	201,448,038	226,084,605	200,985,349
Earnings per share - basic	$ (0.01)	$ (0.02)	$ (0.03)	$ (0.04)
Earnings per share - diluted	$ (0.02)	$ (0.02)	$ (0.05)	$ (0.04)