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

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Amount of noncash expense for share-based payment arrangement.

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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 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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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 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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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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Number of fully vested and expected to vest options outstanding that can be converted into shares under option plan. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

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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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Stock-based Compensation (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Additional General Disclosures [Abstract]
Stock-based compensation expense	$ 410	$ 303	$ 840	$ 626
Compensation Cost Not yet Recognized [Abstract]
Unrecognized compensation expense	$ 2,010		$ 2,010
Weighted average period of recognition			11 months 19 days
Stock Options [Member]
Number of Stock Options [Abstract]
Options outstanding (in shares)	4,908,038		4,908,038
Weighted average exercise price, outstanding (in dollars per share)	$ 1.90		$ 1.90
Vested (in shares)	2,906,381		2,906,381
Exercisable (in shares)	2,906,381		2,906,381
Number of shares available for issuance (in shares)	441,774		441,774
Restricted Stock Units [Member]
Restricted Stock Units [Abstract]
Restricted stock units outstanding (in shares)	119,930		119,930
Restricted stock units issued (in shares)	40,547