Income Taxes - Variations from Federal Statutory Rate (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Expected federal income tax benefit at statutory rate of 21% in 2020 and 2019	$ 147	$ (3,748)
Effect of permanent other differences	239	6
Return to provision adjustments	134	79
State income tax expense (benefit), net of federal benefit tax assets	10	(268)
Valuation allowance	(350)	3,976
Total income tax expense	$ 180	$ 45