Percentage of common stock outstanding to increase shares reserved for issuance.

No definition available.

Name:	ocul_PercentageOfCommonStockOutstandingToIncreaseSharesReservedForIssuance
Namespace Prefix:	ocul_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Non-vested stock options outstanding held by non-employees.

+ References

No definition available.

+ Details

Name:	ocul_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonvestedStockOptionsOutstandingHeldByNonemployees
Namespace Prefix:	ocul_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Shares of common stock to increase shares reserved for issuance.

+ References

No definition available.

+ Details

Name:	ocul_SharesOfCommonStockToIncreaseSharesReservedForIssuance
Namespace Prefix:	ocul_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Aggregate number of common shares reserved for future issuance.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.29)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_CommonStockCapitalSharesReservedForFutureIssuance
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- 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.

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of additional shares authorized for issuance under share-based payment arrangement.

+ References

No definition available.

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=116856206&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of shares issued during the period as a result of an employee stock purchase plan.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(28))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_StatementEquityComponentsAxis=us-gaap_CommonStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PlanNameAxis=ocul_TwoThousandFourteenStockIncentivePlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PlanNameAxis=ocul_TwoThousandFourteenEmployeeStockPurchasePlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Stock-Based Awards - Additional Information (Details) - Common Stock - shares			12 Months Ended
	Jan. 01, 2019	Jan. 01, 2015	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2014
Stock-Based Awards
Issuance of common stock in connection with employee stock purchase plan, shares			130,945	81,455	53,662
2014 Stock Incentive Plan
Stock-Based Awards
Number of shares of common stock authorized for issuance		2,126,907	9,499,615			1,336,907
Increased number of shares of common stock reserved for issuance		1,659,218
Additional number of shares of common stock , percentage		4.00%
Additional number of shares authorized for issuance	1,659,218
Number of shares of common stock available for issuance			636,292
Unvested service-based stock options held by nonemployees			0
2014 Employee Stock Purchase Plan
Stock-Based Awards
Number of shares of common stock authorized for issuance		232,402				207,402
Increased number of shares of common stock reserved for issuance	207,402	207,402
Additional number of shares of common stock , percentage		0.50%
Number of shares of common stock available for issuance			477,967