Employee Benefit Plans - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
401(k) Plan
Defined Contribution Plan Disclosure [Line Items]
Maximum annual contribution by employee, percentage of pre-tax earnings	50.00%
401(k) Plan | U.S. Employees
Defined Contribution Plan Disclosure [Line Items]
Recognized cost of employee benefit plan	$ 2.3	$ 2.0	$ 1.7
Minimum period of service required for matching contribution eligibility	1 year
Minimum required period of service for employer contributions to fully vest	3 years
Defined Contribution Arrangements | Non-U.S. Employees
Defined Contribution Plan Disclosure [Line Items]
Recognized cost of employee benefit plan	$ 0.9	$ 0.7	$ 0.7