Accounts Receivable, Net - Schedule of Accounts Receivable, Net (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Accounts Notes And Loans Receivable [Line Items]
Allowance for doubtful accounts	$ (70)	$ (70)
Total accounts receivable, net	10,731	11,870
Security Products
Accounts Notes And Loans Receivable [Line Items]
Accounts receivable, gross	8,797	10,321
Marine Components
Accounts Notes And Loans Receivable [Line Items]
Accounts receivable, gross	$ 2,004	$ 1,619