Employee Retirement Plan - Additional Information (Details) - USD ($)	3 Months Ended	6 Months Ended
Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Compensation And Retirement Disclosure [Abstract]
Employers contributions to defined contribution plan	$ 39,000	$ 29,000	$ 200,000	$ 100,000
Employees eligibility age to participate in retirement plan			21 years

Amount of discretionary contributions made by an employer to a defined contribution plan.

No definition available.

Name:	us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration