Property and Equipment (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 16,788		$ 16,788		$ 14,602
Less: accumulated depreciation	(3,143)		(3,143)		(2,402)
Property and equipment, net	13,645		13,645		12,200
Depreciation expense	400	$ 300	700	$ 600
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	2,983		$ 2,983		2,976
Leasehold improvements | Minimum
Property, Plant and Equipment [Line Items]
Useful life (in years)			7 years
Leasehold improvements | Maximum
Property, Plant and Equipment [Line Items]
Useful life (in years)			20 years
Machinery & equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	7,569		$ 7,569		7,853
Machinery & equipment | Minimum
Property, Plant and Equipment [Line Items]
Useful life (in years)			1 year
Machinery & equipment | Maximum
Property, Plant and Equipment [Line Items]
Useful life (in years)			12 years
Furniture
Property, Plant and Equipment [Line Items]
Property and equipment, gross	1,715		$ 1,715		1,698
Furniture | Minimum
Property, Plant and Equipment [Line Items]
Useful life (in years)			1 year
Furniture | Maximum
Property, Plant and Equipment [Line Items]
Useful life (in years)			12 years
Construction in progress
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 4,521		$ 4,521		$ 2,075