Benefit Plans - Summary of Contributions to Retirement Plans (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Defined Benefit Plan Disclosure [Line Items]
Contribution to retirement plans	$ 173	$ 276	$ 601	$ 840
US Employees [Member]
Defined Benefit Plan Disclosure [Line Items]
Contribution to retirement plans	164	165	560	484
Foreign Employees [Member]
Defined Benefit Plan Disclosure [Line Items]
Contribution to retirement plans	$ 9	$ 111	$ 41	$ 356