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

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Amount of cost to be recognized for nonvested award under share-based payment arrangement. Excludes share and unit options.

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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 number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Per share or unit weighted-average fair value of nonvested award under share-based payment arrangement. Excludes share and unit options.

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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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Stock-Based Compensation - Service Based Restricted Stock Units (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019
Weighted Average Grant Date Fair Value
Stock based compensation expenses	$ 4,951,820	$ 4,387,554
Restricted stock units - Service based awards
Number of Shares
Outstanding at beginning of period (in shares)	472,959
Granted (in shares)	244,063
Forfeited (in shares)	(28,916)
Vested (in shares)	(224,320)
Outstanding at end of period (in shares)	463,786	472,959
Weighted Average Grant Date Fair Value
Outstanding at beginning of period (in dollars per share)	$ 4.32
Granted (in dollars per share)	4.09
Forfeited (in dollars per share)	4.32
Vested (in dollars per share)	4.19
Outstanding at end of period (in dollars per share)	4.26	$ 4.32
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$ 4.26	$ 4.32	$ 4.26
Stock based compensation expenses	$ 1,600,000	$ 800,000
Unrecognized stock-based compensation expenses			$ 900,000
Restricted stock units - Service based awards \| Minimum
Weighted Average Grant Date Fair Value
Vesting period	1 year
Restricted stock units - Service based awards \| Maximum
Weighted Average Grant Date Fair Value
Vesting period	3 years