Leases - Schedule of Lease Costs and Classification on Unaudited Condensed Consolidated Statements of Comprehensive Loss (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($)
Lease Cost
Net lease cost	$ 3,119
Operating Expenses [Member]
Lessee Lease Description [Line Items]
Operating lease cost	2,758
Selling, General and Administrative Expenses [Member]
Lessee Lease Description [Line Items]
Operating lease cost	137
Depreciation and Amortization [Member]
Financing lease cost
Amortization of leased assets	184
Interest Expense [Member]
Financing lease cost
Interest on lease liabilities	$ 40