Restructuring and Severance - Additional Information (Detail) - USD ($)		3 Months Ended	12 Months Ended
	Feb. 14, 2018	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018
Restructuring Cost And Reserve [Line Items]
Restructuring and severance expenses			$ 14,000	$ 747,000
Restructuring accrual				129,000
3VR
Restructuring Cost And Reserve [Line Items]
Date of acquisition completed	Feb. 14, 2018		Feb. 14, 2018
Restructuring and severance expenses				618,000
Restructuring accrual				129,000
Restructuring accrual reversed		$ 91,000,000
3VR | Facility Rental
Restructuring Cost And Reserve [Line Items]
Restructuring and severance expenses				290,000
3VR | Severance
Restructuring Cost And Reserve [Line Items]
Restructuring and severance expenses			$ 105,000	$ 328,000