Intangible Assets - Schedule of Patent Cost and Other Asset (Detail) - Patents [Member] - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Patent costs	$ 1,686	$ 1,859
Accumulated amortization	(1,354)	(1,434)
Finite-lived intangible assets, net	$ 332	$ 425