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Cash, Cash Equivalents and Investments - Additional Information (Details)
6 Months Ended
Jun. 30, 2019
USD ($)
Cash Cash Equivalents And Short Term Investments [Line Items]  
Investment in continuous unrealized loss position for more than one year $ 0
Maximum [Member]  
Cash Cash Equivalents And Short Term Investments [Line Items]  
Available for sale securities contractual maturity period 1 year