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Fair Value Measurements - Additional information (Details) - USD ($)
$ in Thousands
Mar. 31, 2020
Dec. 31, 2019
Mar. 31, 2019
Dec. 31, 2018
Schedule of Available-for-sale Securities        
Cash and cash equivalents, primarily include money market funds $ 46,857 $ 47,742 $ 50,414 $ 51,612
Fair Value, Measurements, Recurring [Member] | Money market funds (included in cash and cash equivalents) | Quoted Prices in Active Markets for Identical Assets (Level 1)        
Schedule of Available-for-sale Securities        
Cash equivalents, primarily include money market funds $ 46,300 $ 46,200