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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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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Stock-Based Compensation - Performance Based Stock Options (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Number of Shares
Granted (in shares)			199,938
Fair value assumptions:
Stock based compensation expenses	$ 1,501,326	$ 1,365,332	$ 3,018,628	$ 1,811,335
Granted (in shares)			199,938
Stock option awards - Performance based awards
Number of Shares
Outstanding at the beginning of the period (in shares)			388,125
Granted (in shares)		0		0
Outstanding at the end of the period (in shares)	388,125		388,125
Weighted Average Exercise Price
Outstanding at the beginning of the period (in dollars per share)			$ 4.70
Outstanding at the end of the period (in dollars per share)	$ 4.70		$ 4.70
Fair value assumptions:
Stock based compensation expenses	$ 123,901	$ 0	$ 246,440	$ 0
Granted (in shares)		0		0
Unrecognized stock-based compensation expenses	$ 700,000		$ 700,000