Investments - Balance sheet classification of investments (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Investments
Cash equivalents		$ 59,156
Short-term investments		1,000
Total	$ 0	$ 60,156

Amount of short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

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Amount of investment in debt security measured at amortized cost (held-to-maturity).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-Subparagraph (b)
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-Publisher FASB
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Amount of investment in debt security measured at amortized cost (held-to-maturity), classified as current.

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