Note 2 - Acquisitions - Summary of the Estimated Fair Value of Intangible Assets and Their Estimated Useful Lives From the ClariPhy Acquisition (Details) - USD ($) $ in Thousands		12 Months Ended
Dec. 12, 2016	Dec. 31, 2018
Minimum [Member]
Finite-lived intangible assets acquired, estimated useful life (Year)		1 year
Maximum [Member]
Finite-lived intangible assets acquired, estimated useful life (Year)		10 years
ClariPhy Communications Inc.[Member]
Intangible assets acquired, estimated fair value	$ 235,898
ClariPhy Communications Inc.[Member] \| Current In Process Research and Development [Member]
Indefinite-lived intangible assets acquired, estimated fair value	97,340
ClariPhy Communications Inc.[Member] \| Developed Technology Rights [Member]
Finite-lived intangible assets acquired, estimated fair value	$ 66,450
ClariPhy Communications Inc.[Member] \| Developed Technology Rights [Member] \| Minimum [Member]
Finite-lived intangible assets acquired, estimated useful life (Year)	1 year
ClariPhy Communications Inc.[Member] \| Developed Technology Rights [Member] \| Maximum [Member]
Finite-lived intangible assets acquired, estimated useful life (Year)	6 years
ClariPhy Communications Inc.[Member] \| Customer Relationships [Member]
Finite-lived intangible assets acquired, estimated fair value	$ 62,370
Finite-lived intangible assets acquired, estimated useful life (Year)	7 years
ClariPhy Communications Inc.[Member] \| Trade Names [Member]
Finite-lived intangible assets acquired, estimated fair value	$ 1,390
Finite-lived intangible assets acquired, estimated useful life (Year)	5 years
ClariPhy Communications Inc.[Member] \| Computer Software, Intangible Asset [Member]
Finite-lived intangible assets acquired, estimated fair value	$ 8,348
ClariPhy Communications Inc.[Member] \| Computer Software, Intangible Asset [Member] \| Minimum [Member]
Finite-lived intangible assets acquired, estimated useful life (Year)	1 year
ClariPhy Communications Inc.[Member] \| Computer Software, Intangible Asset [Member] \| Maximum [Member]
Finite-lived intangible assets acquired, estimated useful life (Year)	3 years

Amount of increase in assets, excluding financial assets and goodwill, lacking physical substance, from an acquisition.

No definition available.

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- Definition

Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
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Period Type:	duration

- Definition

Amount of increase in assets, excluding financial assets, lacking physical substance with a definite life, from an acquisition.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16265-109275

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- Definition

Amount of increase in assets, excluding financial assets and goodwill, lacking physical substance with an indefinite life, from an acquisition.

+ References

No definition available.

+ Details

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