Income Taxes - Reconciliation of Beginning and Ending Amount of Uncertain Tax Positions (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Balance at beginning of year	$ 577	$ 618	$ 657
Additions based on tax positions related to the current year			11
Reductions for tax positions of prior years	(58)	(41)	(50)
Balance at end of year	$ 519	$ 577	$ 618