Product Revenue Reserves and Allowances - Additional Information (Detail)					1 Months Ended				3 Months Ended										6 Months Ended		12 Months Ended
	Jan. 01, 2021	Dec. 12, 2018 USD ($) Country	Jul. 10, 2017 USD ($)	Mar. 31, 2013 USD ($)	Feb. 29, 2020 USD ($)	Jan. 31, 2020 USD ($)	Aug. 31, 2019 USD ($)	Nov. 30, 2018 USD ($)	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)
Disclosure of Product Revenue Reserves and Allowances [Line Items]
Revenue									$ 8,634,000	$ 2,509,000	$ 7,210,000	$ 2,012,000	$ 2,442,000	$ 486,000	$ 715,000	$ 928,000	$ 933,000	$ 385,000	$ 2,928,000	$ 1,318,000	$ 20,365,000	$ 4,571,000	$ 2,961,000	$ 7,539,000
Accounts receivable									11,368,000				627,000						$ 627,000		11,368,000	627,000
Amended Alimera Agreement [Member]
Disclosure of Product Revenue Reserves and Allowances [Line Items]
Royalty percentage earned from sales of product																			2.00%
Calendar year net sales threshold for increase in royalty rate		$ 75,000,000
Contingently recoverable accumulated commercialization losses			$ 25,000,000																		8,900,000
Partial cancellation of contingently recoverable accumulated commercialization losses in lieu of upfront license fee			$ 10,000,000
Royalty percentage offset for amounts earned above 2% to be applied against balance of accumulated commercialization losses		50.00%
Additional cancellation of contingently recoverable commercialization losses												$ 5,000,000
Revenue																			$ 627,000		2,100,000		723,000
Accrued sales-based royalty income																			588,000		2,000,000		575,000
Amended Alimera Agreement [Member] | Scenario, Forecast [Member]
Disclosure of Product Revenue Reserves and Allowances [Line Items]
Royalty percentage offset for amounts earned above 2% to be applied against balance of accumulated commercialization losses	20.00%
Amended Alimera Agreement [Member] | Minimum [Member]
Disclosure of Product Revenue Reserves and Allowances [Line Items]
Royalty percentage earned from sales of product		6.00%
Amended Alimera Agreement [Member] | Maximum [Member]
Disclosure of Product Revenue Reserves and Allowances [Line Items]
Royalty percentage earned from sales of product		8.00%
Bausch and Lomb [Member]
Disclosure of Product Revenue Reserves and Allowances [Line Items]
Accounts receivable									0				253,000						253,000		$ 0	253,000
OncoSil Medical UK Limited [Member]
Disclosure of Product Revenue Reserves and Allowances [Line Items]
Royalty percentage earned from sales of product																					8.00%
Revenue																					$ 0
Receipt of upfront license fee				$ 100,000
Percentage of non-royalty consideration received from sublicense																					20.00%
Deferred revenue									0												$ 0
License agreement commencement date																					2012-12
Ocumension Therapeutics [Member]
Disclosure of Product Revenue Reserves and Allowances [Line Items]
Receipt of upfront license fee								$ 1,750,000
Deferred revenue									0				$ 30,000						30,000		$ 0	30,000
Potential future payments based on achievement of development and regulatory milestones																					7,250,000
Potential future payments based on achievement of commercial-based milestones																					3,000,000
Development milestone payment received							$ 1,000,000
Ocumension Therapeutics [Member] | Subsequent Event [Member]
Disclosure of Product Revenue Reserves and Allowances [Line Items]
Receipt of upfront license fee					$ 2,000,000
Potential future payments based on achievement of development and regulatory milestones						$ 6,000,000
Potential future payments based on achievement of commercial-based milestones						$ 6,000,000
Ocumension Therapeutics [Member] | Maximum [Member]
Disclosure of Product Revenue Reserves and Allowances [Line Items]
Product supply milestones and development milestones																					7,250,000
Equinox Science, LLC [Member] | Subsequent Event [Member]
Disclosure of Product Revenue Reserves and Allowances [Line Items]
Non-refundable and non-creditable upfront cash payment					1,000,000
Equinox Science, LLC [Member] | Maximum [Member] | Subsequent Event [Member]
Disclosure of Product Revenue Reserves and Allowances [Line Items]
Payment upon achievement of development and regulatory milestones					$ 50,000,000
ILUVIEN [Member] | Europe [Member]
Disclosure of Product Revenue Reserves and Allowances [Line Items]
Number of countries in which lead licensed product received regulatory approval | Country		17
Royalty Income [Member]
Disclosure of Product Revenue Reserves and Allowances [Line Items]
Revenue																			1,045,000	717,000	2,180,000	1,946,000	1,618,000	970,000
Royalty Income [Member] | Bausch and Lomb [Member]
Disclosure of Product Revenue Reserves and Allowances [Line Items]
Revenue																			456,000		204,000		1,000,000	970,000
Collaborative Research and Development [Member]
Disclosure of Product Revenue Reserves and Allowances [Line Items]
Revenue																				$ 601,000		$ 2,625,000
Collaborative Research and Development [Member] | OncoSil Medical UK Limited [Member]
Disclosure of Product Revenue Reserves and Allowances [Line Items]
Revenue																					100,000
Collaborative Research and Development [Member] | Feasibility Study Agreement [Member]
Disclosure of Product Revenue Reserves and Allowances [Line Items]
Revenue																			15,000		135,000		1,100,000	211,000
Deferred revenue									$ 15,000												15,000
License Agreement and MOU [Member] | Ocumension Therapeutics [Member]
Disclosure of Product Revenue Reserves and Allowances [Line Items]
Revenue																					1,100,000
Product [Member]
Disclosure of Product Revenue Reserves and Allowances [Line Items]
Revenue																			0		16,824,000		0	0
Product [Member] | Ocumension Therapeutics [Member]
Disclosure of Product Revenue Reserves and Allowances [Line Items]
Revenue																					91,000
License and Collaboration Agreement [Member]
Disclosure of Product Revenue Reserves and Allowances [Line Items]
Revenue																			1,883,000		1,361,000		$ 1,343,000	$ 6,569,000
License and Collaboration Agreement [Member] | Ocumension Therapeutics [Member]
Disclosure of Product Revenue Reserves and Allowances [Line Items]
Revenue																			$ 1,700,000		$ 1,000,000