Restructuring and Severance (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Restructuring And Related Activities [Abstract]
Balance at beginning of period	$ 129
Restructuring expense for the period	14	$ 747
Net payments during the period	$ (143)	(618)
Balance at end of period		$ 129