Stock-Based Compensation - Summary of Restricted Stock Units (Details) shares in Thousands	9 Months Ended
Sep. 30, 2019 $ / shares shares
RSUs
RSUs
RSUs Outstanding at beginning of period (in shares) \| shares	227
Granted (in shares) \| shares	613
Vested (in shares) \| shares	(75)
Forfeited (in shares) \| shares	(110)
RSUs Outstanding at end of period (in shares) \| shares	655
Weighted- Average Grant Date Fair Value (in dollars per share)
RSUs outstanding at the beginning of the period (in dollars per share) \| $ / shares	$ 37.69
Granted (in dollars per share) \| $ / shares	20.04
Exercised (in dollars per share) \| $ / shares	38.59
Forfeited (in dollars per share) \| $ / shares	26.35
RSUs outstanding at the ending of the period (in dollars per share) \| $ / shares	$ 22.93
PSUs
RSUs
RSUs Outstanding at beginning of period (in shares) \| shares	0
Granted (in shares) \| shares	79
Vested (in shares) \| shares	0
Forfeited (in shares) \| shares	0
RSUs Outstanding at end of period (in shares) \| shares	79
Weighted- Average Grant Date Fair Value (in dollars per share)
RSUs outstanding at the beginning of the period (in dollars per share) \| $ / shares	$ 0
Granted (in dollars per share) \| $ / shares	19.20
Exercised (in dollars per share) \| $ / shares	0
Forfeited (in dollars per share) \| $ / shares	0
RSUs outstanding at the ending of the period (in dollars per share) \| $ / shares	$ 19.20

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

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)(1)(iv)(3)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

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- Definition

Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
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- Definition

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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-Paragraph 2
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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

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- Definition

The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Per share or unit weighted-average fair value of nonvested award under share-based payment arrangement. Excludes share and unit options.

+ References

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-Publisher FASB
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-Paragraph 2
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- Definition

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

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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-Paragraph 2
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- Definition

The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

+ References

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-Publisher FASB
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