Significant Accounting Policies - Additional Information (Details)	1 Months Ended	3 Months Ended	12 Months Ended
	Dec. 31, 2020 USD ($)	Mar. 31, 2021 USD ($) Segment	Dec. 31, 2019 USD ($)	Jan. 31, 2019 USD ($)
Basis Of Presentation And Significant Accounting Policies [Line Items]
Number of operating segments | Segment		1
Operating lease right-of-use asset	$ 936,000	$ 1,426,000
Operating lease liabilities		$ 1,900,000
ASU 2016-02
Basis Of Presentation And Significant Accounting Policies [Line Items]
Change in accounting principle, accounting standards update, adopted		true
Change in accounting principle, accounting standards update, adoption date		Jan. 01, 2020
ASU 2018-07
Basis Of Presentation And Significant Accounting Policies [Line Items]
Change in accounting principle, accounting standards update, adopted		true
Change in accounting principle, accounting standards update, adoption date		Jan. 01, 2020
Alzheimers Association
Basis Of Presentation And Significant Accounting Policies [Line Items]
Research grant awarded				$ 1,000,000.0
Grants received		$ 224,000	$ 776,000
National Institute on Aging of the National Institutes of Health
Basis Of Presentation And Significant Accounting Policies [Line Items]
Research grant awarded	15,200,000
Grants received	7,800,000
Remaining grant to be received	$ 7,400,000