Summary of Significant Accounting Policies - Cash and Cash Equivalents (Details) $ in Millions	Dec. 31, 2020 USD ($)
Accounting Policies [Abstract]
Cash, cash equivalents and available for sale securities	$ 210.0

Cash And Cash Equivalents And Debt Securities Available For Sale

No definition available.

Name:	opht_CashAndCashEquivalentsAndDebtSecuritiesAvailableForSale
Namespace Prefix:	opht_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant