Short-Term Investments (Details) $ in Thousands	12 Months Ended
Dec. 31, 2019 USD ($) instrument	Dec. 31, 2018 USD ($) instrument
Short-Term Investments
Amortized Cost	$ 26,345	$ 22,280
Gross Unrealized Losses		(4)
Fair Value	$ 26,345	$ 22,276
Number of short term investments in unrealized loss position \| instrument	4	7
Number of short term investments in an unrealized loss position more than 12 months \| instrument	0	0
Aggregate fair value of the investments in an unrealized loss position	$ 3,400	$ 7,300
Commercial Paper
Short-Term Investments
Amortized Cost	1,993
Fair Value	1,993
Corporate debt securities
Short-Term Investments
Amortized Cost	3,352	7,280
Gross Unrealized Losses		(4)
Fair Value	3,352	7,276
Reverse repurchase agreements
Short-Term Investments
Amortized Cost	21,000	15,000
Fair Value	$ 21,000	$ 15,000

The amount of short-term investments at amortized cost.

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- Definition

This item represents the aggregate fair value of short term investments, that have been in a continuous unrealized loss position for less than twelve months.

+ References

No definition available.

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Number of short term investment positions that have been in a continuous unrealized loss position for greater than or equal to a year for which an other-than-temporary impairment (OTTI) has not been recognized in the income statement.

+ References

No definition available.

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- Definition

Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on short-term investments in debt and equity securities.

+ References

No definition available.

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Number of Short term investment positions in a continuous unrealized loss position for which an other-than-temporary impairment (OTTI) has not been recognized in the income statement.

+ References

No definition available.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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Amount of investments including trading securities, available-for-sale securities, held-to-maturity securities, and short-term investments classified as other and current.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(4))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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-Name Accounting Standards Codification
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
-Topic 942
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
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Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
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