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Cash, Cash Equivalents and Short-Term Investments - Summary of Amortized Cost And Recorded Basis of T-bills in Short Term Investments (Details) - USD ($) $ in Thousands | Sep. 30, 2019 | Dec. 31, 2018
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Cash, Cash Equivalents, and Short-term Investments [Abstract] |  |
Short-term investments | $ 104,565 | $ 105,256

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- Definition Amount of investment in debt security measured at amortized cost (held-to-maturity), classified as current. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109979856&loc=d3e26626-111562 + Details
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