Revenue - Disaggregation of Revenue (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Disclosure of Product Revenue Reserves and Allowances [Line Items]
Revenues	$ 4,122	$ 7,210	$ 11,611	$ 9,222
YUTIQ [Member]
Disclosure of Product Revenue Reserves and Allowances [Line Items]
Revenues	2,879	6,705	6,454	7,248
DEXYCU [Member]
Disclosure of Product Revenue Reserves and Allowances [Line Items]
Revenues	827		1,939	684
Product [Member]
Disclosure of Product Revenue Reserves and Allowances [Line Items]
Revenues	$ 3,706	$ 6,705	$ 8,393	$ 7,932