Restatement of Previously Issued Unaudited Interim Condensed Consolidated Financial Statements (Details 4) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net loss	$ (13,119)	$ (919)	$ (17,921)	$ (88)
Additional paid-in capital	118,524		118,524		$ 106,312
Total stockholders’ equity	38,712		38,712		$ 44,753
As Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net loss	(20,716)		(25,518)
Additional paid-in capital	126,532		126,532
Total stockholders’ equity	39,123		39,123
Adjustment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net loss	7,597		7,597
Additional paid-in capital	(8,008)		(8,008)
Total stockholders’ equity	$ (411)		$ (411)