Summary of Significant Accounting Policies - Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Property, plant and equipment at cost	$ 120,018	$ 111,674
Less: accumulated depreciation and amortization	(96,927)	(84,720)
Property, plant and equipment, net	23,091	26,954
Machinery and Equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment at cost	91,984	83,900
Furniture and Fixtures
Property, Plant and Equipment [Line Items]
Property, plant and equipment at cost	6,620	6,377
Leasehold Improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment at cost	$ 21,414	$ 21,397