Credit Facility - Additional Information (Detail) - USD ($)	6 Months Ended
Jun. 30, 2018	Dec. 31, 2017
Line of Credit Facility [Line Items]
Fair value of warrants issued	$ 266,000
Pacific Western Bank [Member]
Line of Credit Facility [Line Items]
Proceeds from credit facility	$ 2,000,000
Debt instrument annual interest rate	5.25%
Credit facility outstanding	$ 1,400,000
Loan repayment period	36 months
Term Loan [Member] \| Pacific Western Bank [Member]
Line of Credit Facility [Line Items]
Credit facility amount	$ 5,000,000
Term Loan [Member] \| Prime Rate [Member] \| Pacific Western Bank [Member]
Line of Credit Facility [Line Items]
Debt instrument variable annual interest rate	2.00%
Tranche B Loans [Member] \| Pacific Western Bank [Member]
Line of Credit Facility [Line Items]
Proceeds from credit facility	$ 3,000,000
Pacific Western Credit Facility [Member]
Line of Credit Facility [Line Items]
Net of debt discount amount	$ 52,000	$ 59,000

Fair value of warrant issued.

No definition available.

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Namespace Prefix:	aldx_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Loan repayment term.

+ References

No definition available.

+ Details

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- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

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- Definition

Amount, after accumulated amortization, of debt discount (premium).

+ References

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- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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+ Details

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Namespace Prefix:	us-gaap_
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Balance Type:	credit
Period Type:	instant

- Definition

The effective interest rate during the reporting period.

+ References

+ Details

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

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- Definition

Amount of cash inflow from contractual arrangement with the lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.

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