Weighted average remaining life of warrants or rights outstanding.

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- Definition

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

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- Definition

Exercise price per share or per unit of warrants or rights outstanding.

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- Definition

Number of warrants or rights outstanding.

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No definition available.

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- Definition

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

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Weighted-average period over which cost not yet recognized is expected to be recognized for 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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- Definition

Amount of cost to be recognized for option under share-based payment arrangement.

+ References

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- Definition

Amount of cash inflow from exercise of option under share-based payment arrangement.

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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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No definition available.

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- Definition

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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- Definition

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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- Definition

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

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- Definition

Fair value of options vested. Excludes equity instruments other than options, for example, but not limited to, share units, stock appreciation rights, restricted stock.

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Share-Based Compensation - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Aug. 03, 2018	Dec. 03, 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding to purchase shares of common stock (in shares)	17,710,657		17,710,657		25,087,416
Warrants outstanding (in shares)	1,100,000		1,100,000		900,000
Share-based payments expense	$ 2,000,000.0	$ 3,400,000	$ 4,000,000.0	$ 5,600,000
Unrecognized compensation expense related to non-vested share options	$ 10,400,000		$ 10,400,000
Weighted average period for recognition related to non-vested stock options (in years)			1 year 3 months 18 days
Total intrinsic value of shares exercised			$ 5,249,163	59,847
Total fair value of vested shares			$ 2,800,000	5,500,000
Weighted average exercise price of warrants (in dollars per share)	$ 4.00		$ 4.00
Weighted average remaining life of warrants (in years)			1 year 1 month 6 days
2010 Stock Incentive Plan ("the Plan")
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized for issuance (in shares)						56,800,000	31,500,000
Number of options available for issuance (in shares)	26,800,000		26,800,000
Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding to purchase shares of common stock (in shares)	17,700,000		17,700,000
Cash received from options exercised			$ 7,800,000	$ 0
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding to purchase shares of common stock (in shares)	100,000		100,000
Unrecognized compensation cost related to unvested restricted shares	$ 0		$ 0