Commitments and Contingencies - Additional Information (Detail) - USD ($)	1 Months Ended	12 Months Ended
	Aug. 31, 2019	Dec. 31, 2021	Dec. 31, 2020	Apr. 30, 2019	Mar. 31, 2009
Other Commitments [Line Items]
Claims paid to date related to indemnification issues		$ 0
Accruals or expenses related to indemnification issues		0	$ 0
University of Pennsylvania [Member]
Other Commitments [Line Items]
Accrued expenses		8,200,000	100,000
University of Pennsylvania [Member] | Maximum [Member]
Other Commitments [Line Items]
Upfront fee, milestone fees				$ 20,500,000
GlaxoSmithKline LLC [Member]
Other Commitments [Line Items]
Accrued expenses		16,300,000	$ 13,100,000
Milestone payment obligation					$ 1,500,000
Clearside Biomedical Inc. [Member]
Other Commitments [Line Items]
Milestone payment obligation		$ 3,000,000.0
Payments against exercise of license option	$ 1,600,000
Clearside Biomedical Inc. [Member] | Maximum [Member]
Other Commitments [Line Items]
Milestone payment obligation	$ 136,000,000.0