Restructuring Activities - Summary of Charges Related to Restructuring Activities (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Restructuring Cost And Reserve [Line Items]
Accrued Restructuring Expenses		$ 921	$ 628
Expenses		4,783	1,289
Less: Payments	$ (400)	(5,638)	(996)
Accrued Restructuring Expenses	921	66	921
Severance Benefits and Related Costs Due to Workforce Reduction [Member]
Restructuring Cost And Reserve [Line Items]
Accrued Restructuring Expenses		921	628
Expenses		4,783	1,289
Less: Payments		(5,638)	(996)
Accrued Restructuring Expenses	$ 921	$ 66	$ 921