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Cash Equivalents and Marketable Securities - Summary of Realized and Unrealized Gains (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Investments, Debt and Equity Securities [Abstract]      
Net gains recognized on marketable equity investments $ 132 $ 107 $ 582
Less: Net gains recognized on sale of marketable equity investments 0 0 (316)
Unrealized gains at the end of the period $ 132 $ 107 $ 266