Leases - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Lessee Lease Description [Line Items]
Total rent expense	$ 400,000	$ 400,000	$ 1,200,000	$ 1,100,000
Lessee, Operating Lease, Existence of Option to Extend [true false]			true
Weighted average remaining operating lease term	2 years 10 months 24 days		2 years 10 months 24 days
Weighted average discount rate of operating lease	6.40%		6.40%
Sublease rental income due in future under non-cancelable subleases	$ 1,600,000		$ 1,600,000
Operating lease liabilities, cash paid	400,000		1,400,000
Sublease rental income	$ 0		$ 200,000
Minimum
Lessee Lease Description [Line Items]
Remaining lease term	1 year		1 year
Maximum
Lessee Lease Description [Line Items]
Remaining lease term	7 years		7 years
Operating leases, options to extend leases term	5 years		5 years