EMPLOYEE BENEFIT PLAN (Details) - Employee 401(k) Plan - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Contribution Plan
Employer matching contribution as a percentage of the employee's contribution	50.00%
Percentage of contribution vested each year	25.00%
Vesting period of contribution by the company	4 years
Matching contributions by the company	$ 2.0	$ 0.7	$ 0.6
Maximum
Defined Contribution Plan
Annual employee contribution limit as a percent of compensation	15.00%
Percent of employee's earnings eligible for employer matching contribution	6.00%