Financial Instruments Investments in Marketable Debt Securities - Additional Information (Detail) $ in Thousands	6 Months Ended	12 Months Ended
Jun. 30, 2020 USD ($) Security	Dec. 31, 2019 USD ($)
Schedule Of Available For Sale Securities [Line Items]
Investments in available-for-sale debt securities, excluding corporate debt securities and commercial paper included in cash and cash equivalents	$ 7,925	$ 36,144
Available-for-sale, weighted-average remaining contractual life	1 month 6 days
Debt Securities
Schedule Of Available For Sale Securities [Line Items]
Number of available-for-sale securities in unrealized loss positions \| Security	1
Maximum
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale securities, period of unrealized loss positions	12 months	12 months
Minimum
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale securities, period of unrealized loss positions	12 months	12 months
Cash and Cash Equivalents
Schedule Of Available For Sale Securities [Line Items]
Investments in available-for-sale debt securities, excluding corporate debt securities and commercial paper included in cash and cash equivalents	$ 1,200

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), classified as current.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 45
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-URI http://asc.fasb.org/extlink&oid=121558606&loc=SL82898722-210454

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-SubTopic 10
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Number of investment positions in available-for-sale investments in a continuous unrealized loss position for which an other-than-temporary impairment (OTTI) has not been recognized in the income statement.

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