Organization and Nature of Business; Basis of Presentation; Principles of Consolidation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Depreciation and amortization expense	$ 2,200	$ 2,300	$ 1,800
Research and development | Reclassification
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Depreciation and amortization expense	1,100	1,400	1,100
Sales, general and administrative | Reclassification
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Depreciation and amortization expense	$ 632	$ 983	$ 672