v3.23.1
Document and Entity Information - shares
 3 Months Ended
Mar. 31, 2023
May 03, 2023
Document Document and Entity Information [Abstract]    
Document Type 10-Q  
Document Quarterly Report true  
Document Transition Report false  
Document Period End Date Mar. 31, 2023  
Entity File Number 001-34475  
Entity Registrant Name OMEROS CORPORATION  
Entity Incorporation, State or Country Code WA  
Entity Tax Identification Number 91-1663741  
Entity Address, Address Line One 201 Elliott Avenue West  
Entity Address, City or Town Seattle  
Entity Address, State or Province WA  
Entity Address, Postal Zip Code 98119  
City Area Code 206  
Local Phone Number 676-5000  
Title of 12(b) Security Common Stock  
Trading Symbol OMER  
Security Exchange Name NASDAQ  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Accelerated Filer  
Entity Small Business true  
Entity Emerging Growth Company false  
Entity Shell Company false  
Entity Common Stock, Shares Outstanding   62,828,765
Current Fiscal Year End Date --12-31  
Document Fiscal Year Focus 2023  
Document Fiscal Period Focus Q1  
Entity Central Index Key 0001285819  
Amendment Flag false