Property, Plant and Equipment - Schedule of Property, Plant and Equipment (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Property Plant And Equipment [Line Items]
Property, plant, and equipment, gross	$ 233,061	$ 212,932
Accumulated depreciation	(169,448)	(150,205)
Property, plant, and equipment, net	63,613	62,727
Buildings [Member]
Property Plant And Equipment [Line Items]
Property, plant, and equipment, gross	4,096	3,731
Plant and equipment [Member]
Property Plant And Equipment [Line Items]
Property, plant, and equipment, gross	50,159	46,470
Instrumentation [Member]
Property Plant And Equipment [Line Items]
Property, plant, and equipment, gross	93,252	82,327
Computer software [Member]
Property Plant And Equipment [Line Items]
Property, plant, and equipment, gross	52,565	49,696
Furniture and fixtures [Member]
Property Plant And Equipment [Line Items]
Property, plant, and equipment, gross	8,024	7,328
Construction in progress [Member]
Property Plant And Equipment [Line Items]
Property, plant, and equipment, gross	1,628	2,201
Finance lease assets [Member]
Property Plant And Equipment [Line Items]
Property, plant, and equipment, gross	$ 23,337	$ 21,179