Employee Benefit Plan - Additional Information (Details) - 401 (k) Plan - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Contribution Plan Disclosure [Line Items]
Eligibility age of employees for plan	21 years
Employee minimum service period	90 days
Employer contribution amount	$ 481,000	$ 420,000	$ 375,000