v3.20.1

Stock-Based Compensation - Options (Details) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2020 USD ($) $ / shares shares
Stock options
Number of Options
Outstanding balance at the beginning of the period (in shares) | shares	4,373,895
Granted (in shares) | shares	8,597
Exercised (in shares) | shares	(37,275)
Forfeited (in shares) | shares	(7,252)
Expired (in shares) | shares	(27,399)
Outstanding balance at the end of the period (in shares) | shares	4,310,566
Exercisable at the end of the period (in shares) | shares	3,079,102
Weighted-Average Exercise Price per Share
Outstanding balance at the beginning of the period (in dollars per share) | $ / shares	$ 34.24
Granted (in dollars per share) | $ / shares	19.61
Exercised (in dollars per share) | $ / shares	10.30
Forfeited (in dollars per share) | $ / shares	66.61
Expired (in dollars per share) | $ / shares	38.73
Outstanding balance at the end of the period (in dollars per share) | $ / shares	34.34
Exercisable at the end of the period (in dollars per share) | $ / shares	$ 21.82
Intrinsic value of options exercisable at the end of the period | $	$ 22.7
Employee Stock
Weighted-Average Exercise Price per Share
Weighted-average remaining contractual term of options exercisable at the end of the period (in years)	2 years 9 months 7 days

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- Definition

The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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Number of options or other stock instruments for which the right to exercise has lapsed under the terms of the plan agreements.

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The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

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

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

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

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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

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