401 (K) PLAN	12 Months Ended
Dec. 31, 2017
Compensation And Retirement Disclosure [Abstract]
401 (K) PLAN	15. 401 (K) PLAN The Company sponsors a 401 (k) Plan (“the Plan”) which is a defined contribution plan. It is available to all employees who are age 21 or older. Participants may make voluntary contributions and the Company makes matching contributions according to the Plan’s matching formula. For employees who started before January 1, 2016, matching contributions fully vest after one year of service. For employees who started on and after January 1, 2016, matching contributions vest on a straight line basis over three years. The expense related to the Plan primarily consists of the Company’s matching contributions. Expense related to the Plan totaled $1.4 million, $1.2 million and $0.9 million for the years ended December 31, 2017, 2016 and 2015, respectively.

401 (K) PLAN

12 Months Ended

Dec. 31, 2017

Compensation And Retirement Disclosure [Abstract]

15. 401 (K) PLAN

The Company sponsors a 401 (k) Plan (“the Plan”) which is a defined contribution plan. It is available to all employees who are age 21 or older. Participants may make voluntary contributions and the Company makes matching contributions according to the Plan’s matching formula. For employees who started before January 1, 2016, matching contributions fully vest after one year of service. For employees who started on and after January 1, 2016, matching contributions vest on a straight line basis over three years. The expense related to the Plan primarily consists of the Company’s matching contributions.

Expense related to the Plan totaled $1.4 million, $1.2 million and $0.9 million for the years ended December 31, 2017, 2016 and 2015, respectively.