Operations and Basis of Presentation - Additional Information (Detail) $ in Thousands, Surgery in Millions	1 Months Ended	9 Months Ended		12 Months Ended
	Oct. 31, 2020 USD ($)	Sep. 30, 2020 USD ($) Product _People Case	Sep. 30, 2019 USD ($)	Dec. 31, 2018 Surgery	Dec. 31, 2019 USD ($)
Operations [Line Items]
Number of products approved | Product		2
Accumulated deficit		$ 495,211			$ 465,286
Working capital		34,700
Cash and cash equivalents		28,726			$ 22,214
Proceeds from issuance of common stock		$ 24,802	$ 20,755
Subsequent Event [Member]
Operations [Line Items]
Cash and cash equivalents	$ 30,500
Subsequent Event [Member] | At-the-Market Offering [Member]
Operations [Line Items]
Proceeds from issuance of common stock	$ 5,700
YUTIQ [Member]
Operations [Line Items]
Number of new cases of blindness annually | Case		30,000
YUTIQ [Member] | Minimum [Member]
Operations [Line Items]
Number of people affected by posterior segment of eye in U.S. each year | _People		60,000
YUTIQ [Member] | Maximum [Member]
Operations [Line Items]
Number of people affected by posterior segment of eye in U.S. each year | _People		100,000
DEXYCU [Member]
Operations [Line Items]
Number of cataract surgeries performed in U.S. | Surgery				3.8