Revenue - Additional Information (Detail) - USD ($)	1 Months Ended					3 Months Ended		9 Months Ended
	Aug. 31, 2020	Feb. 29, 2020	Jan. 31, 2020	Aug. 31, 2019	Nov. 30, 2018	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Disclosure of Product Revenue Reserves and Allowances [Line Items]
Revenue						$ 15,695,000	$ 2,509,000	$ 27,306,000	$ 11,732,000
Icon Bioscience Inc [Member]
Disclosure of Product Revenue Reserves and Allowances [Line Items]
Sales-based royalty expense						$ 908,000		$ 1,300,000
Percentage of accelerated milestone payment received						20.00%		20.00%
Amended Alimera Science Inc Agreement [Member]
Disclosure of Product Revenue Reserves and Allowances [Line Items]
Revenue						$ 437,000	475,000	$ 1,600,000	1,500,000
Ocumension Therapeutics [Member]
Disclosure of Product Revenue Reserves and Allowances [Line Items]
Receipt of upfront license fee	$ 9,500,000	$ 2,000,000.0			$ 1,750,000
Potential future payments based on achievement of development and regulatory milestones	6,000,000.0		$ 6,000,000.0					7,250,000
Potential future payments based on achievement of commercial-based milestones	6,000,000.0		$ 6,000,000.0					3,000,000.0
Development milestone payment received				$ 1,000,000.0
Potential future payments based on achievement of combined remaining development and sales milestone.	11,750,000
Potential future payments based on achievement of remaining development and regulatory milestones	6,250,000
Potential future payments based on achievement of remaining commercial-based milestones	3,000,000.0
Deferred revenue						0		0		$ 0
Ocumension Therapeutics [Member] | Maximum [Member]
Disclosure of Product Revenue Reserves and Allowances [Line Items]
Product supply milestones and development milestones								7,250,000
Upon achievement of milestones	$ 21,250,000
Royalty Income [Member]
Disclosure of Product Revenue Reserves and Allowances [Line Items]
Revenue						402,000	446,000	1,565,000	1,666,000
Royalty Income [Member] | Amended Alimera Science Inc Agreement [Member]
Disclosure of Product Revenue Reserves and Allowances [Line Items]
Revenue						402,000	446,000	1,600,000	1,400,000
License and Collaboration Agreement [Member]
Disclosure of Product Revenue Reserves and Allowances [Line Items]
Revenue						9,535,000	1,054,000	11,590,000	1,125,000
License and Collaboration Agreement [Member] | Ocumension Therapeutics [Member]
Disclosure of Product Revenue Reserves and Allowances [Line Items]
Revenue						9,500,000		11,500,000
Collaborative Research and Development [Member]
Disclosure of Product Revenue Reserves and Allowances [Line Items]
Revenue						0	$ 25,000	15,000	$ 25,000
Deferred revenue						$ 300,000		$ 300,000		$ 15,000