Selected Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Revenues	$ 43,256	$ 42,476	$ 40,628	$ 43,114	$ 43,770	$ 43,636	$ 42,325	$ 41,444	$ 169,474	$ 171,175	$ 179,561
Operating income (loss)	149	(1,560)	(2,346)	584	3,589	3,325	2,410	1,382	(3,173)	10,706	22,153
Net (loss) income	$ 189	$ (840)	$ (1,172)	$ 345	$ 21,384	$ 3,727	$ 1,498	$ 854	$ (1,479)	$ (15,306)	$ 13,979
Basic and diluted net income (loss) per common share (usd per share)	$ 0.01	$ (0.04)	$ (0.06)	$ 0.02	$ (1.07)	$ 0.19	$ 0.07	$ 0.04	$ (0.08)	$ (0.76)	$ 0.68
Reduction of DTA					$ 24,200
Cost of revenue									$ 32,408	$ 28,418	$ 30,649
Adjustments
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Operating income (loss)		$ (359)	$ (196)	$ (166)
Net (loss) income		$ (359)	$ (196)	$ (116)
Cost of revenue	$ 771

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The aggregate cost of goods produced and sold and services rendered during the reporting period.

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