Certain Balance Sheet Accounts - Contract Royalty Asset and Accounts Receivable, Net (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Certain Balance Sheet Accounts
Short-term contract royalty asset	$ 43,794	$ 44,319
Long-term contract royalty asset	126,812	140,251
Total OMIDRIA contract royalty asset	170,606	184,570
Royalty and trade receivables, net	13,669	36,505
Sublease and other receivables	810	1,650
Total receivables, net	$ 14,479	38,155
Chargeback and product return allowances		$ 2,000

Amount of contract royalty asset.

No definition available.

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Namespace Prefix:	omer_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of contract royalty asset due to the entity within one year of the balance sheet date (or one operating cycle, if longer).

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

Amount of contract royalty asset due to the entity in after one year or beyond the operating cycle, if longer.

+ References

No definition available.

+ Details

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Namespace Prefix:	omer_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount, after allowance for credit loss, of right to consideration from customer for product sold and service rendered in normal course of business.

+ References

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+ Details

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- References

No definition available.

+ Details

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Balance Type:	na
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- Definition

Amount of liability for consideration received or receivable from customer which is not included in transaction price, when consideration is expected to be refunded to customer, classified as current.

+ References

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-Publisher FASB
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+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

Amount, after allowance, of receivables classified as other, due within one year or the operating cycle, if longer.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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- Definition

The total amount due to the entity within one year of the balance sheet date (or one operating cycle, if longer) from outside sources, including trade accounts receivable, notes and loans receivable, as well as any other types of receivables, net of allowances established for the purpose of reducing such receivables to an amount that approximates their net realizable value.

+ References

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+ Details

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Period Type:	instant