Acquisition of Icon Bioscience, Inc - Additional Information (Detail) - USD ($)		1 Months Ended	12 Months Ended
	Mar. 28, 2018	Apr. 30, 2019	Dec. 31, 2019
Business Acquisition [Line Items]
Percentage of partnering income received to be paid quarterly as earn-out consideration	20.00%
DEXYCU [Member]
Business Acquisition [Line Items]
Finite-lived intangible asset expected amortization life			11 years 3 months
Icon Bioscience Inc [Member]
Business Acquisition [Line Items]
Development milestone payment due following the first commercial sales of DEXYCU	$ 15,000,000
Maximum of potential sales milestone payments	$ 95,000,000
Quarterly percentage earn-out consideration due on product net sales	12.00%
Increased percentage earn-out on product net sales if net sales and partnering revenue exceed $200 million in a given year	16.00%
Contingent cash payments, description			These include but are not limited to (i) a one-time development milestone of $15.0 million payable in cash upon the first commercial sale of DEXYCU in the U.S., (ii) sales milestone payments totaling up to $95.0 million upon the achievement of certain sales thresholds and subject to certain Centers for Medicare & Medicaid Services (“CMS”) reimbursement conditions set forth in the Merger Agreement, (iii) quarterly earn-out payments equal to 12% on net sales of DEXYCU in a given year, which earn-out payments will increase to 16% of net sales of DEXYCU in such year beginning in the calendar quarter for such year to the extent aggregate annual DEXYCU consideration exceeds $200.0 million in such year, (iv) quarterly earn-out payments equal to 20% of partnering revenue received by the Company for DEXYCU outside of the U.S., and (v) single-digit percentage quarterly earn-out payments with respect to net sales and/or partnering income, if any, resulting from future clinical development, regulatory approval and commercialization of any other product candidates the Company acquired in the Icon Acquisition
Transaction costs	$ 2,000,000
Icon Bioscience Inc [Member] | Minimum [Member]
Business Acquisition [Line Items]
Threshold level of annual aggregate consideration above which the 16% royalty on net sales applies in any given year			$ 200,000,000
Icon Bioscience Inc [Member] | DEXYCU [Member]
Business Acquisition [Line Items]
Development milestone payment due following the first commercial sales of DEXYCU			15,000,000
Estimated working capital adjustment at closing			127,000
Accrued development milestone consideration paid following the first commercial sale of DEXYCU	15,000,000	$ 15,000,000
Purchase price of acquisition	$ 32,000,000
Finite-lived intangible asset expected amortization life	13 years
Accrued sales-based royalty expense			$ 781,000