Commitments and Contingencies - Additional Information (Details) - USD ($)		1 Months Ended			12 Months Ended			16 Months Ended
	Oct. 01, 2018	May 31, 2016	Sep. 30, 2014	Dec. 31, 2012	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jun. 30, 2018
Loss Contingencies [Line Items]
Security deposit provided to lessor					$ 100,000
Rent expense under operating leases					$ 1,800,000	$ 1,700,000	$ 1,300,000
Lease Agreements [Member]
Loss Contingencies [Line Items]
Lease term	36 months							16 months
Annual rent	$ 100,000
December 2012, Amended Facility Lease Agreement [Member]
Loss Contingencies [Line Items]
Lease expiration date				Sep. 30, 2016
September 2014, Amended Facility Lease Agreement [Member]
Loss Contingencies [Line Items]
Lease expiration date			Sep. 30, 2019
Lease improvement allowance maximum amount			$ 600,000
May 2016, Amended Facility Lease Agreement [Member]
Loss Contingencies [Line Items]
Lease expiration date		Sep. 30, 2021
Lease improvement allowance maximum amount		$ 400,000