Aggregate Intrinsic Value [Abstract]

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- Definition

Share-based Compensation Arrangement By Share-based Payment Award, Award Vesting Rights, Stock Price Trigger, Consecutive Term

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- Definition

Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Share Price Threshold

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- Definition

Weighted Average Remaining Contractual Term [Abstract]

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- Definition

The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

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The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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- Definition

The risk-free interest rate assumption that is used in valuing an option on its own shares.

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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.

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- Definition

Gross number of share options (or share units) granted during the period.

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- Definition

The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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- Definition

Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

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- Definition

Number of options outstanding, including both vested and non-vested options.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(i)-(ii)
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

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- Definition

Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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- Definition

Amount by which current fair value of underlying stock exceeds exercise price of fully vested and expected to vest options outstanding. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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- Definition

Number of fully vested and expected to vest options outstanding that can be converted into shares under option plan. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Weighted-average exercise price, at which grantee can acquire shares reserved for issuance, for fully vested and expected to vest options outstanding. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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- Definition

Percentage of vesting of award under share-based payment arrangement.

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Expected term of award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
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-Topic 718
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 14.D.2)
-URI http://asc.fasb.org/extlink&oid=115993241&loc=d3e301413-122809

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Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Weighted average remaining contractual term for fully vested and expected to vest options outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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Stock-based Compensation - Performance-based Stock Option Awards (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	1 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)		437
Expected volatility		51.60%	38.90%	42.80%
Expected term (in years)		6 years 3 months	6 years 3 months	6 years 3 months
Dividend yield		0.00%	0.00%	0.00%
Weighted-average fair value per option granted (in dollars per share)		$ 6.52	$ 6.30	$ 8.38
Outstanding at the end of the period (in shares)		4,828	5,089
Vested and expected to vest at the end of the period (in shares)		4,553
Weighted Average Exercise Price, outstanding at the end of the period (in dollars per share)		$ 9.44	$ 9.82
Weighted Average Exercise Price, vested and expected to vest at the end of the period (in dollars per share)		$ 9.16
Weighted Average Remaining Contractual Term
Outstanding		6 years 3 days	6 years 10 months 9 days
Vested and expected to vest		5 years 10 months 28 days
Aggregate Intrinsic Value
Outstanding		$ (1,880)	$ 51,556
Vested and expected to vest		$ (488)
Performance-based stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	300
Risk free interest rate	1.83%
Expected volatility	65.00%
Expected term (in years)	10 years
Dividend yield	0.00%
Weighted-average fair value per option granted (in dollars per share)	$ 6.68
Outstanding at the end of the period (in shares)		268	268
Vested and expected to vest at the end of the period (in shares)		268
Weighted Average Exercise Price, outstanding at the end of the period (in dollars per share)		$ 10.27	$ 10.27
Weighted Average Exercise Price, vested and expected to vest at the end of the period (in dollars per share)		$ 10.27
Weighted Average Remaining Contractual Term
Outstanding		6 years 2 months 1 day	7 years 2 months 1 day
Vested and expected to vest		6 years 2 months 1 day
Aggregate Intrinsic Value
Outstanding		$ (326)	$ 2,592
Vested and expected to vest		$ (326)
Performance-based stock options \| Vest on March 1, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	50.00%
Performance-based stock options \| Vest on March 1, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	50.00%
Performance-based stock options \| Class A Common Stock \| Tranche One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights, share price threshold (in dollars per share)	$ 13.35
Vesting percentage	33.33%
Consecutive term	90 days
Performance-based stock options \| Class A Common Stock \| Tranche Two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights, share price threshold (in dollars per share)	$ 16.43
Vesting percentage	33.33%
Consecutive term	90 days
Performance-based stock options \| Class A Common Stock \| Tranche Three
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting rights, share price threshold (in dollars per share)	$ 19.51
Vesting percentage	33.33%
Consecutive term	90 days