Restructuring and Severance - Additional Information (Detail) - USD ($)	3 Months Ended			9 Months Ended
	Sep. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Restructuring Cost And Reserve [Line Items]
Restructuring and severance expenses	$ 163,000		$ (87,000)	$ 1,645,000	$ (101,000)
Sublease income received	0			200,000
3VR
Restructuring Cost And Reserve [Line Items]
Restructuring and severance expenses	163,000			1,645,000
Sublease income received		$ 198,000		0
3VR | Facility Rental
Restructuring Cost And Reserve [Line Items]
Restructuring and severance expenses	18,000			1,416,000
3VR | Severance
Restructuring Cost And Reserve [Line Items]
Restructuring and severance expenses	145,000			229,000
3VR | Impairment of ROU Operating Lease Asset
Restructuring Cost And Reserve [Line Items]
Restructuring and severance expenses	$ 1,199,000			$ 1,199,000