Stockholders' Equity - Restricted Stock and Performance Based Restricted Stock Units Activity (Details) - $ / shares	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Weighted- Average Grant Date Fair Value
Granted, weighted-average grant date fair value (in dollars per share)	$ 2.29	$ 5.63	$ 3.85
Restricted Stock Units (RSUs) And Performance Based Restricted Stock Units (PSUs)
Shares
Outstanding beginning balance (in shares)	4,725,353
Granted (in shares)	3,518,762
Vested (in shares)	(2,267,342)
Forfeited (in shares)	(1,422,430)
Outstanding ending balance (in shares)	4,554,343	4,725,353
Weighted- Average Grant Date Fair Value
Outstanding beginning balance, weighted-average exercise price (in dollars per share)	$ 7.43
Granted, weighted-average grant date fair value (in dollars per share)	3.44
Vested, weighted-average grant date fair value (in dollars per share)	6.77
Forfeited, weighted-average exercise price (in dollars per share)	5.82
Outstanding ending balance, weighted-average exercise price (in dollars per share)	$ 5.17	$ 7.43

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)
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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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-Topic 718
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-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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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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-Name Accounting Standards Codification
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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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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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-Name Accounting Standards Codification
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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.

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