Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Tax Disclosure [Abstract]
(Provision for) benefit from income taxes	$ (86)	$ 79	$ (371)	$ 65
Effective income tax rate	1.03%	(1.83%)	0.99%	(0.47%)
Unrecognized tax benefits	$ 500		$ 500
Unrecognized tax benefits that would favorably impact effective tax rate	$ 400		$ 400
Statutory income tax rates			21.00%