Leases - Schedule of Future Minimum Lease Payments (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Leases [Abstract]
2019 (excluding the six months ended June 30, 2019)	$ 3,355
2019		$ 5,616
2020	6,483	4,963
2021	6,618	5,507
2022	4,732	3,861
2023	871
Thereafter	943
Total lease payments	23,002	$ 19,947
Less: imputed interest	(3,333)
Operating lease, liability	$ 19,669