Note 8 - OMIDRIA Royalty Obligation - Schedule of Principal and Interest Payments on Royalty Obligations (Details) $ in Thousands	Dec. 31, 2023 USD ($)
2024, principal	$ 8,576
2024, interest	11,424
2024, annual cap	20,000
2025, principal	14,641
2025, interest	10,359
2025, annual cap	25,000
2026, principal	16,081
2026, interest	8,919
2026, annual cap	25,000
2027, principal	17,664
2027, interest	7,336
2027, annual cap	25,000
2028, principal	19,402
2028, interest	5,598
2028, annual cap	25,000
Thereafter, principal	48,762
Thereafter, interest	4,988
Thereafter, annual cap	53,750
Total scheduled payments, principal	125,126
Total scheduled payments, interest	48,624
Total scheduled payments, annual cap	$ 173,750

Amount of total interest portion of royalty obligation.

No definition available.

Name:	omer_RoyaltyObligationInterestPaymentsDue
Namespace Prefix:	omer_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of interest portion of royalty obligation due after fifth fiscal year following current fiscal year.

+ References

No definition available.

+ Details

Name:	omer_RoyaltyObligationInterestPaymentsDueAfterYearFive
Namespace Prefix:	omer_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of interest portion of royalty obligation to be paid in next fiscal year following current fiscal year.

+ References

No definition available.

+ Details

Name:	omer_RoyaltyObligationInterestPaymentsDueNextTwelveMonths
Namespace Prefix:	omer_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of interest portion of royalty obligation to be paid in fifth fiscal year following current fiscal year.

+ References

No definition available.

+ Details

Name:	omer_RoyaltyObligationInterestPaymentsDueYearFive
Namespace Prefix:	omer_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of interest portion of royalty obligation to be paid in fourth fiscal year following current fiscal year.

+ References

No definition available.

+ Details

Name:	omer_RoyaltyObligationInterestPaymentsDueYearFour
Namespace Prefix:	omer_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of interest portion of royalty obligation to be paid in third fiscal year following current fiscal year.

+ References

No definition available.

+ Details

Name:	omer_RoyaltyObligationInterestPaymentsDueYearThree
Namespace Prefix:	omer_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of interest portion of royalty obligation to be paid in second fiscal year following current fiscal year.

+ References

No definition available.

+ Details

Name:	omer_RoyaltyObligationInterestPaymentsDueYearTwo
Namespace Prefix:	omer_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of total royalty obligation.

+ References

No definition available.

+ Details

Name:	omer_RoyaltyObligationPaymentsDue
Namespace Prefix:	omer_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of total royalty obligation due after fifth fiscal year following current fiscal year.

+ References

No definition available.

+ Details

Name:	omer_RoyaltyObligationPaymentsDueAfterYearFive
Namespace Prefix:	omer_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of total royalty obligation to be paid in next fiscal year following current fiscal year.

+ References

No definition available.

+ Details

Name:	omer_RoyaltyObligationPaymentsDueNextTwelveMonths
Namespace Prefix:	omer_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of total royalty obligation to be paid in fifth fiscal year following current fiscal year.

+ References

No definition available.

+ Details

Name:	omer_RoyaltyObligationPaymentsDueYearFive
Namespace Prefix:	omer_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of total royalty obligation to be paid in fourth fiscal year following current fiscal year.

+ References

No definition available.

+ Details

Name:	omer_RoyaltyObligationPaymentsDueYearFour
Namespace Prefix:	omer_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of total royalty obligation to be paid in third fiscal year following current fiscal year.

+ References

No definition available.

+ Details

Name:	omer_RoyaltyObligationPaymentsDueYearThree
Namespace Prefix:	omer_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of total royalty obligation to be paid in second fiscal year following current fiscal year.

+ References

No definition available.

+ Details

Name:	omer_RoyaltyObligationPaymentsDueYearTwo
Namespace Prefix:	omer_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of total principal portion of royalty obligation.

+ References

No definition available.

+ Details

Name:	omer_RoyaltyObligationPrincipalPaymentsDue
Namespace Prefix:	omer_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of principal portion of royalty obligation due after fifth fiscal year following current fiscal year.

+ References

No definition available.

+ Details

Name:	omer_RoyaltyObligationPrincipalPaymentsDueAfterYearFive
Namespace Prefix:	omer_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of principal portion of royalty obligation to be paid in next fiscal year following current fiscal year.

+ References

No definition available.

+ Details

Name:	omer_RoyaltyObligationPrincipalPaymentsDueNextTwelveMonths
Namespace Prefix:	omer_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of principal portion of royalty obligation to be paid in fifth fiscal year following current fiscal year.

+ References

No definition available.

+ Details

Name:	omer_RoyaltyObligationPrincipalPaymentsDueYearFive
Namespace Prefix:	omer_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of principal portion of royalty obligation to be paid in fourth fiscal year following current fiscal year.

+ References

No definition available.

+ Details

Name:	omer_RoyaltyObligationPrincipalPaymentsDueYearFour
Namespace Prefix:	omer_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of principal portion of royalty obligation to be paid in third fiscal year following current fiscal year.

+ References

No definition available.

+ Details

Name:	omer_RoyaltyObligationPrincipalPaymentsDueYearThree
Namespace Prefix:	omer_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of principal portion of royalty obligation to be paid in second fiscal year following current fiscal year.

+ References

No definition available.

+ Details

Name:	omer_RoyaltyObligationPrincipalPaymentsDueYearTwo
Namespace Prefix:	omer_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant