Property, Plant and Equipment - Schedule of Property, Plant and Equipment (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Property Plant And Equipment [Line Items]
Property, plant, and equipment, gross	$ 212,932	$ 181,862
Accumulated depreciation	(150,205)	(139,027)
Property, plant, and equipment, net	62,727	42,835
Buildings [Member]
Property Plant And Equipment [Line Items]
Property, plant, and equipment, gross	3,731	3,746
Plant and equipment [Member]
Property Plant And Equipment [Line Items]
Property, plant, and equipment, gross	46,470	45,744
Instrumentation [Member]
Property Plant And Equipment [Line Items]
Property, plant, and equipment, gross	82,327	75,542
Computer software [Member]
Property Plant And Equipment [Line Items]
Property, plant, and equipment, gross	49,696	47,322
Furniture and fixtures [Member]
Property Plant And Equipment [Line Items]
Property, plant, and equipment, gross	7,328	6,599
Construction in progress [Member]
Property Plant And Equipment [Line Items]
Property, plant, and equipment, gross	2,201	$ 2,909
Finance lease assets [Member]
Property Plant And Equipment [Line Items]
Property, plant, and equipment, gross	$ 21,179