Significant Accounting Policies - Net Income (Loss) Per Share (Details) - shares shares in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Schedule of reconciliation of shares used to calculate basic and diluted earnings per share
Weighted average shares outstanding used to compute basic earnings per share	21,499	10,745
Incremental shares issuable upon the assumed exercise of stock options	92	45
Unvested restricted stock and restricted stock units	459	521
Shares used to compute diluted earnings per share	22,050	11,311

Number of additional shares included in diluted EPS for potentially dilutive effect of nonvested equity-based payment award containing forfeitable rights to dividends or dividend equivalents, whether paid or unpaid.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
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-SubTopic 10
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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of share based payment arrangements using the treasury stock method.

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The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

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Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

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