Leases - Summary of Other Information (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($)
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$ 10
Right-of-use assets obtained in exchange for new lease liabilities:
Operating leases	81
Finance leases	$ 134
Weighted-average remaining lease term:
Operating leases	8 years 6 months
Finance leases	2 years
Weighted-average remaining discount rate:
Operating leases	10.00%
Finance leases	9.20%