Significant Items Making up Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Components Of Deferred Tax Assets And Liabilities [Abstract]
Allowances not currently deductible for tax purposes	$ 978	$ 451
Net operating loss carryforwards	44,068	45,196
Operating lease liabilities	312	513
General carryforwards	16,433	16,242
Stock-based compensation	1,487	1,291
Accrued and other	1,961	1,990
Deferred Tax Assets, Gross, Total	65,239	65,683
Less valuation allowance	(62,441)	(62,699)
Deferred Tax Assets, Net of Valuation Allowance, Total	2,798	2,984
Depreciation and amortization	(925)	(1,032)
Operating lease right-of-use assets	(10)	(169)
State income taxes	(1,863)	(1,783)
Deferred Tax Liabilities, Gross, Total	$ (2,798)	$ (2,984)