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FAIR VALUE MEASUREMENTS - Assets Measured On a Recurring Basis (Details) - USD ($)
$ in Thousands
Mar. 31, 2021
Dec. 30, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Marketable securities $ 40,914 $ 36,887
Level 1 | Mutual Fund [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Marketable securities $ 40,914 $ 36,887