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Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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The highest quantity of shares an employee can purchase under the plan per period.

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Number of equity instruments other than options outstanding, including both vested and non-vested instruments.

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Number of additional shares authorized for issuance under share-based payment arrangement.

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Number of shares authorized for issuance under share-based payment arrangement.

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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

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Stock-Based Compensation - Narrative (Details) - USD ($)		3 Months Ended
	May 25, 2016	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Stock Based Compensation Details [Line Items]
Unrecognized compensation costs		$ 1,200,000
Employee Stock Option
Stock Based Compensation Details [Line Items]
Compensation expense		$ 400,000	$ 300,000
Number of options forfeited (in shares)		66,588
Shares of common stock options outstanding (in shares)		8,081,381		5,167,739
Restricted Stock
Stock Based Compensation Details [Line Items]
Compensation expense		$ 100,000	$ 100,000
Unrecognized compensation costs		$ 36,000.0
Restricted Stock \| Minimum
Stock Based Compensation Details [Line Items]
Vesting period		1 year
Restricted Stock \| Maximum
Stock Based Compensation Details [Line Items]
Vesting period		3 years
Plan 2009
Stock Based Compensation Details [Line Items]
Additional shares authorized (in shares)	2,000,000
Number of options forfeited (in shares)	2,500,000
Plan 2016
Stock Based Compensation Details [Line Items]
Shares approved and authorized (in shares)	4,000,000
Maximum number of shares to any individual (in shares)	1,000,000
Shares of common stock options outstanding (in shares)		185,564		136,496,000
Shares available for grant (in shares)		921,089		2,334,731
Plan 2016 \| Common Stock
Stock Based Compensation Details [Line Items]
Shares of common stock options outstanding (in shares)		4,278,773		2,835,131,000
Plan 2016 \| Restricted Stock
Stock Based Compensation Details [Line Items]
RSUs outstanding (in shares)		13,612		62,680,000