Maturities of Lease Liabilities (Detail) $ in Thousands	Mar. 31, 2019 USD ($)
Years Ended December 31,
Operating leases, 2019	$ 481
Operating leases, 2020	656
Operating leases 2021	676
Operating leases, 2022	696
Operating leases, 2023	175
Operating leases, thereafter	0
Operating leases, total mimimum lease payments	2,684
Operating leases, less amount representing interest	(296)
Operating leases present value	2,388
Finance leases, 2019	21
Finance leases, 2020	27
Finance leases, 2021	9
Finance leases, 2022	0
Finance leases, 2023	0
Finance leases, thereafter	0
Finance leases, total minimum lease payments	57
Finance leases, less amount representing interest	(7)
Finance leases present value	$ 50