Stockholder's Equity (Details) - Stock Options [Member] - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018
Stock option activity, number of shares
Outstanding options, beginning of period	803,320
Granted	60,000
Exercised	0
Forfeited	(44,195)
Outstanding options, end of period	819,125
Options vested and expected to vest	819,125
Exercisable	614,941
Weighted average exercise price per share
Outstanding options, beginning of period	$ 2.89
Granted	2.14
Exercised	0.00
Forfeited	2.82
Outstanding options, end of period	2.84
Options vested and expected to vest	2.84
Exercisable	$ 3.03
Additional disclosure
Options outstanding, weighted average remaining contractual term	8 years 2 months 26 days
Options vested and expected to vest, weighted average remaining contractual term	8 years 2 months 26 days
Options exercisable, weighted average remaining contractual term	8 years 1 month 6 days
Options outstanding, aggregate intrinsic value	$ 0	$ 54
Options vested and expected to vest, aggregate intrinsic value	0
Options exercisable, aggregate intrinsic value	$ 0

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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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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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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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Gross number of share options (or share units) granted during the period.

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Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

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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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Amount by which current fair value of underlying stock exceeds exercise price of fully vested and expected to vest options outstanding. 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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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 exercise price, at which grantee can acquire shares reserved for issuance, for fully vested and expected to vest options outstanding. 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 price at which option holders acquired shares when converting their stock options into shares.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated.

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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

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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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Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Number of share options (or share units) exercised during the current period.

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