Summary of Significant Accounting Policies - Additional Information (Details)	12 Months Ended
	Dec. 31, 2019 USD ($) FinancialInstitution Segment	Jan. 01, 2019 USD ($)	Dec. 31, 2018 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Maximum maturity period of short-term, highly liquid investments for qualifying cash equivalents	90 days
Minimum maturity period of investments for qualifying marketable securities	90 days
Restricted cash, non-current	$ 1,595,000		$ 1,198,000
Number of accredited financial institution where cash, cash equivalents and marketable securities maintained | FinancialInstitution	1
Deferred offering costs	$ 0		$ 0
Impairment losses on long-lived assets	$ 0
Number of operating segments | Segment	1
Operating lease, right-of-use asset	$ 14,858,000	$ 16,672,000
Operating lease, right-of-use liabilities	$ 21,708,000
Minimum
Summary Of Significant Accounting Policies [Line Items]
Percentage of likelihood of tax benefit being realized	50.00%
Laboratory Equipment
Summary Of Significant Accounting Policies [Line Items]
Property and equipment depreciated or amortized over useful life	5 years
Computer Equipment
Summary Of Significant Accounting Policies [Line Items]
Property and equipment depreciated or amortized over useful life	3 years
Furniture and Office Equipment
Summary Of Significant Accounting Policies [Line Items]
Property and equipment depreciated or amortized over useful life	3 years
Leasehold Improvements
Summary Of Significant Accounting Policies [Line Items]
Description of property and equipment depreciated or amortized over useful life	Leasehold improvements are amortized over the shorter of the lease term or 10 years.
Leasehold Improvements | Maximum
Summary Of Significant Accounting Policies [Line Items]
Property and equipment depreciated or amortized over useful life	10 years