Employee Benefit Plan (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Employee benefit plan
Entity's matching contribution as a percentage of each participating employee's contribution	50.00%
Vesting period	3 years
Total employer matching contributions to the Plan	$ 558	$ 745	$ 461
Maximum
Employee benefit plan
Employer matching contribution as a percentage of employee contribution	3.00%