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Stock-based Compensation - Compensation Cost Recognized for Stock Options and Restricted Stock Awards (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Compensation cost recognized for the stock options and restricted stock awards [Abstract]
Total compensation cost for share-based payment arrangements recognized in the statement of operations (net of tax of $0)	$ 49	$ 143	$ 355	$ 753

X

- Definition

Compensation cost recognized for the stock options and restricted stock awards.

+ References

No definition available.

+ Details

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- Definition

Amount of noncash expense for share-based payment arrangement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585

+ Details

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