Commitments and Contingencies - Additional Information (Details) - USD ($)	1 Months Ended		3 Months Ended		6 Months Ended
	Nov. 30, 2018	Aug. 31, 2017	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Commitments And Contingencies [Line Items]
Operating sublease, right-of-use asset			$ 2,013,000		$ 2,013,000		$ 0
Operating lease right-of-use asset			3,003,000		3,003,000
Operating lease costs			300,000	$ 200,000	600,000	$ 100,000
Contingent liabilities			$ 0		$ 0		$ 0
Office and Laboratory Space
Commitments And Contingencies [Line Items]
Operating lease commencement year					2018-11
Operating lease expiration year					2023-02
Operating lease, option to extend, description					The Lease commenced in November 2018 and will expire in February 2023, however, the Company has the option to extend the Lease for a 12-month period.
Operating lease, renewal term			12 months		12 months
Operating lease right-of-use asset			$ 1,000,000		$ 1,000,000
Operating lease, liabilities			$ 1,100,000		$ 1,100,000
Operating lease, remaining term					3 years 9 months
Estimated incremental borrowing rate to recognize lease liability, percentage			7.00%		7.00%
Office and Laboratory Space | COI Pharmaceuticals, Inc
Commitments And Contingencies [Line Items]
Lessee, operating sublease, option to terminate, description					In November 2018, the Company amended the 2017 Sublease to provide the Company with a one-time right to terminate as of March 1, 2024, subject to certain conditions and fees.
Lessee, operating sublease, termination date	Mar. 01, 2024
Lessee, operating sublease, expiration year	2027-02
Operating sublease, right-of-use asset			$ 2,000,000		$ 2,000,000
Operating sublease, aggregate lease liability			$ 2,100,000		$ 2,100,000
Operating sublease, remaining term					7 years 8 months
Estimated incremental borrowing rate to recognize lease liability, percentage			8.50%		8.50%
California | Office and Laboratory Space | COI Pharmaceuticals, Inc
Commitments And Contingencies [Line Items]
Sublease entered date		2017-08