Summary of Significant Accounting Policies - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Australian Research and Development Tax Incentive | Australian Taxation Office
Summary Of Significant Accounting Policies [Line Items]
Tax incentive receivable, reductions to research and development expense	$ 0.2	$ 0.2	$ 0.4	$ 0.3
Accounts Payable And Accrued Expenses
Summary Of Significant Accounting Policies [Line Items]
Accrued research and development expenses	$ 4.2		$ 4.2		$ 2.8