Component of Property and Equipment (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Property Plant And Equipment [Line Items]
Manufacturing equipment	$ 12,104	$ 10,086
Lab equipment	6,686	6,280
Computer equipment	4,760	4,010
Furniture and fixtures	1,629	1,566
Leasehold improvements	10,873	8,942
Assets in progress	1,176	2,298
Property, Plant and Equipment, Gross	37,228	33,182
Less accumulated depreciation and amortization	(20,609)	(16,008)
Total	$ 16,619	$ 17,174
Manufacturing Equipment | Minimum
Property Plant And Equipment [Line Items]
Estimated Useful Lives (In years)	5 years
Manufacturing Equipment | Maximum
Property Plant And Equipment [Line Items]
Estimated Useful Lives (In years)	14 years
Lab Equipment | Minimum
Property Plant And Equipment [Line Items]
Estimated Useful Lives (In years)	5 years
Lab Equipment | Maximum
Property Plant And Equipment [Line Items]
Estimated Useful Lives (In years)	13 years
Computer Equipment
Property Plant And Equipment [Line Items]
Estimated Useful Lives (In years)	3 years
Furniture and Fixtures | Minimum
Property Plant And Equipment [Line Items]
Estimated Useful Lives (In years)	3 years
Furniture and Fixtures | Maximum
Property Plant And Equipment [Line Items]
Estimated Useful Lives (In years)	13 years
Leasehold Improvements | Minimum
Property Plant And Equipment [Line Items]
Estimated Useful Lives (In years)	5 years
Leasehold Improvements | Maximum
Property Plant And Equipment [Line Items]
Estimated Useful Lives (In years)	8 years