Restructuring Activities - Summary of Charges Related to Restructuring Activities (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Restructuring Cost And Reserve [Line Items]
Accrued Restructuring Expenses	$ 66,000	$ 921,000
Expenses	0	347,000
Less: Payments	(20,000)	(1,059,000)
Accrued Restructuring Expenses	46,000	209,000
Severance Benefits and Related Costs Due to Workforce Reduction [Member]
Restructuring Cost And Reserve [Line Items]
Accrued Restructuring Expenses	66,000	921,000
Expenses		347,000
Less: Payments	(20,000)	(1,059,000)
Accrued Restructuring Expenses	$ 46,000	$ 209,000