Share-based compensation arrangement by share-based payment award, number of share-based employee compensation plans.

No definition available.

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- Definition

Unrecognized cost of unvested share-based compensation awards.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

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- Definition

Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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- Definition

Unrecognized cost of unvested options awarded to employees as compensation.

+ References

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- Definition

Estimated period over which an employee is required to provide service in exchange for the equity-based payment award, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

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- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(iii)(2)
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

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- Definition

Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (d)(2)
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

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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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- Definition

Percentage of vesting of share-based compensation awards.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

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Stockholders' Equity - Additional Information (Details) shares in Millions, $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2019 USD ($) Plan shares	Mar. 31, 2018 USD ($)	Dec. 31, 2018 shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of share-based employee compensation plans \| Plan	3
Pre-2017 RSUs
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation cost	$ 140.0
Weighted average recognition period	1 year 6 months
Post-2017 RSUs
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation cost	$ 1,400.0
Weighted average recognition period	3 years 1 month 6 days
Service condition satisfied, years	4 years
Post-2017 RSUs \| First Year
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting percentage	10.00%
Post-2017 RSUs \| Second Year
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting percentage	20.00%
Post-2017 RSUs \| Third Year
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting percentage	30.00%
Post-2017 RSUs \| Fourth Year
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting percentage	40.00%
RSUs
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
RSUs vested but not yet settled \| shares	20.8		22.4
RSAs
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation cost	$ 48.4
Weighted average recognition period	3 years 3 months 18 days
Fair value of vested shares	$ 4.6	$ 1.6
Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted average recognition period	2 years 3 months 18 days
Unrecognized compensation cost related to stock options granted and assumed	$ 32.3