Leases - Schedule of Maturity Analysis of Minimum Lease Payment Obligation Under Non-cancellable Operating Leases (Detail) $ in Thousands	Jun. 30, 2019 USD ($)
Lessee Lease Description [Line Items]
Remaining 2019	$ 2,126
2020	2,103
2021	1,207
2022 and thereafter	0
Total lease payments	5,436
Less: interest	324
Present value of lease liabilities	5,112
Office Lease [Member]
Lessee Lease Description [Line Items]
Remaining 2019	1,540
2020	1,567
2021	924
2022 and thereafter	0
Total lease payments	4,031
Less: interest	260
Present value of lease liabilities	3,771
Leased Vehicles and Office Equipment [Member]
Lessee Lease Description [Line Items]
Remaining 2019	586
2020	536
2021	283
2022 and thereafter	0
Total lease payments	1,405
Less: interest	64
Present value of lease liabilities	$ 1,341