Property, Plant and Equipment - Summary of Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Property Plant And Equipment [Line Items]
Less: accumulated depreciation and amortization	$ (13,350)	$ (15,154)
Property, plant and equipment, net (note 6)	4,466	3,554
Research Equipment [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment	8,424	8,683
Office Furniture and Equipment [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment	832	994
Computer Equipment [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment	1,539	2,641
Leasehold Improvements [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment	$ 7,021	$ 6,390

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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