Stock-Based Compensation - Schedule of Outstanding Options (Details) - USD ($)	3 Months Ended	12 Months Ended
Mar. 31, 2019	Dec. 31, 2017	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Beginning options outstanding (in shares)	264,246
Stock options exercised (in shares)	0
Ending options outstanding (in shares)	264,246
Options exercisable (in shares)	264,246
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Options outstanding, weighted average exercise price (in usd per share)	$ 2.84		$ 2.84
Stock options exercised, weighted average exercise price (in usd per share)	0.00
Options exercisable, weighted average exercise price (in usd per share)	$ 2.84
Options outstanding, weighted average remaining contractual term	2 years 8 months 12 days	2 years 8 months 12 days
Options exercisable, weighted average remaining contractual term	2 years 8 months 12 days
Options outstanding, aggregate intrinsic value	$ 2,019		$ 2,019
Options exercisable, aggregate intrinsic value	$ 2,019

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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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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-Publisher FASB
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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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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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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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