Employee Stock Benefit Plans - Range of Exercise Prices (Details) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
Dec. 31, 2019 USD ($) $ / shares shares
Share-based compensation by range of exercise prices:
Stock Options Outstanding (in shares) \| shares	4,946
Stock Options Outstanding, Weighted Average Remaining Contractual Life	5 years 1 month 17 days
Stock Options Outstanding, Weighted Average Exercise Price (USD per share)	$ 4.01
Stock Options Outstanding, Aggregate Intrinsic Value \| $	$ 16,804
Stock Options Exercisable, Stock Options Vested and Exercisable (in shares) \| shares	4,425
Stock Options Exercisable, Weighted Average Remaining Contractual Life	4 years 10 months 13 days
Stock Options Exercisable, Weighted Average Exercise Price (USD per share)	$ 3.73
Stock Options Exercisable, Aggregate Intrinsic Value \| $	$ 16,281
$0.69 to $1.99
Share-based compensation by range of exercise prices:
Stock Options Outstanding (in shares) \| shares	268
Stock Options Outstanding, Weighted Average Exercise Price (USD per share)	$ 1.22
Stock Options Exercisable, Stock Options Vested and Exercisable (in shares) \| shares	264
Stock Options Exercisable, Weighted Average Exercise Price (USD per share)	$ 1.22
Range of Exercise Prices, minimum	0.69
Range of Exercise Prices, maximum	$ 1.99
Exercise Price Range, Range Two [Member]
Share-based compensation by range of exercise prices:
Stock Options Outstanding (in shares) \| shares	3,337
Stock Options Outstanding, Weighted Average Exercise Price (USD per share)	$ 3.41
Stock Options Exercisable, Stock Options Vested and Exercisable (in shares) \| shares	3,337
Stock Options Exercisable, Weighted Average Exercise Price (USD per share)	$ 3.41
Range of Exercise Prices, minimum	2.00
Range of Exercise Prices, maximum	$ 4.00
$4.01 to $7.25
Share-based compensation by range of exercise prices:
Stock Options Outstanding (in shares) \| shares	1,341
Stock Options Outstanding, Weighted Average Exercise Price (USD per share)	$ 6.06
Stock Options Exercisable, Stock Options Vested and Exercisable (in shares) \| shares	824
Stock Options Exercisable, Weighted Average Exercise Price (USD per share)	$ 5.83
Range of Exercise Prices, minimum	4.01
Range of Exercise Prices, maximum	$ 7.34

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

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
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The floor of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

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The number of shares reserved for issuance pertaining to the outstanding exercisable stock options as of the balance sheet date in the customized range of exercise prices for which the market and performance vesting condition has been satisfied.

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The number of shares reserved for issuance pertaining to the outstanding stock options as of the balance sheet date for all option plans in the customized range of exercise prices.

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The ceiling of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

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Weighted average exercise price as of the balance sheet date for those equity-based payment arrangements exercisable and outstanding.

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

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The weighted average price as of the balance sheet date at which grantees could acquire the underlying shares with respect to all outstanding stock options which are in the customized range of exercise prices.

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

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