Property Plant and Equipment Net - Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Apr. 30, 2016 a
Property, Plant and Equipment [Line Items]
Depreciation expense	$ 11,900	$ 9,600	$ 6,700
Property, plant and equipment, net	181,900	114,572
Norton, Massachusetts
Property, Plant and Equipment [Line Items]
Undeveloped land acquired | a				12
Norton, Massachusetts | Land and costs related to the construction of manufacturing facility
Property, Plant and Equipment [Line Items]
Property, plant and equipment, net	$ 140,500	$ 73,200