Provision Benefit for Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Foreign	$ 274	$ 274	$ 255
Federal	0	0	0
State	0	0	2
Total current	274	274	257
Foreign	0	0	0
Federal	23	6	4
State	22	4	2
Total deferred	45	10	6
Provision for income taxes	$ 319	$ 284	$ 263