Employee Benefit Plan

12 Months Ended

Dec. 31, 2017

Compensation And Retirement Disclosure [Abstract]

Employee Benefit Plan

6. Employee Benefit Plan

The Company sponsors a defined contribution retirement plan (“401k Plan”) under Section 401(k) of the Internal Revenue Code. The 401k Plan covers substantially all employees who meet specified service requirements. Under the 401k Plan, the Company may, at its discretion, match 100% of the first 3% of an employee’s salary plus 50% of the next 2% up to the maximum allowed by the Internal Revenue Code. The Company’s contributions to the 401k Plan for the years ended December 31, 2017, 2016 and 2015 were $1.3 million, $1.1 million and $1.0 million, respectively, and are included within insurance operating expenses in the accompanying consolidated statements of operations and comprehensive loss.