Notes Payable	6 Months Ended
Jun. 30, 2016
Debt Disclosure [Abstract]
Notes Payable	Notes Payable In December 2015, we entered into the Loan Agreement pursuant to which we borrowed $50.0 million. In May 2016, we entered into the First Amendment to the Loan Agreement (the Amendment) whereby we accelerated the borrowing of the additional $20.0 million potentially available to us under the Loan Agreement. After deducting all loan initiation costs, we received $19.9 million in net proceeds. The Amendment did not modify the interest rate or any terms or covenants of the Loan Agreement except to increase the final payment fee rate applicable to the additional $20.0 million borrowed from 5.25% to 6.25% reflecting the accelerated draw-down of the additional loan. As of June 30, 2016, our outstanding principal balance is $70.0 million and our loan maturity fee is $5.0 million. Interest under the Loan Agreement accrues on the loans at an annual rate of 9.25%. Our monthly interest-only payments of $539,600 are due through July 1, 2017. Beginning August 1, 2017, monthly principal and interest payments of $2.6 million are due through the January 1, 2020 maturity date. In connection with the Amendment, we issued warrants to purchase an aggregate of 100,602 shares of Omeros common stock (the Warrants) to Oxford and EWB at the then current market price of $9.94 per share. We accounted for the Warrants as a discount to our notes payable. See Note 9 for further discussion of the Warrants. We accounted for the Amendment as a debt modification and, accordingly, the unamortized discount and debt issuance costs associated with the Loan Agreement are being amortized to interest expense using the effective interest method over the remaining term of the Loan Agreement. The Loan Agreement contains covenants that require us to maintain $10.0 million in restricted cash and certain eligible term investments and limit or restrict our ability to enter into certain transactions. In addition, we are required to either meet an annual OMIDRIA net revenue minimum for 2016 of $70.0 million and quarterly OMIDRIA revenue minimums in 2017 and 2018, or maintain 50% of the then-outstanding note payable balance in restricted cash and certain eligible term investments. The Loan Agreement also includes provisions related to events of default, the occurrence of a material adverse effect and changes of control. The occurrence of an event of default could result in the acceleration of the Loan Agreement and, under certain circumstances, could increase our interest rate by 5.0% per annum during the period of default. There was no event of default under the Loan Agreement as of June 30, 2016. As of June 30, 2016, the remaining unamortized discount and debt issuance costs associated with the debt were $5.1 million and $440,700, respectively.

Notes Payable

In December 2015, we entered into the Loan Agreement pursuant to which we borrowed $50.0 million. In May 2016, we entered into the First Amendment to the Loan Agreement (the Amendment) whereby we accelerated the borrowing of the additional $20.0 million potentially available to us under the Loan Agreement. After deducting all loan initiation costs, we received $19.9 million in net proceeds. The Amendment did not modify the interest rate or any terms or covenants of the Loan Agreement except to increase the final payment fee rate applicable to the additional $20.0 million borrowed from 5.25% to 6.25% reflecting the accelerated draw-down of the additional loan. As of June 30, 2016, our outstanding principal balance is $70.0 million and our loan maturity fee is $5.0 million. Interest under the Loan Agreement accrues on the loans at an annual rate of 9.25%. Our monthly interest-only payments of $539,600 are due through July 1, 2017. Beginning August 1, 2017, monthly principal and interest payments of $2.6 million are due through the January 1, 2020 maturity date. In connection with the Amendment, we issued warrants to purchase an aggregate of 100,602 shares of Omeros common stock (the Warrants) to Oxford and EWB at the then current market price of $9.94 per share. We accounted for the Warrants as a discount to our notes payable. See Note 9 for further discussion of the Warrants.

We accounted for the Amendment as a debt modification and, accordingly, the unamortized discount and debt issuance costs associated with the Loan Agreement are being amortized to interest expense using the effective interest method over the remaining term of the Loan Agreement.

The Loan Agreement contains covenants that require us to maintain $10.0 million in restricted cash and certain eligible term investments and limit or restrict our ability to enter into certain transactions. In addition, we are required to either meet an annual OMIDRIA net revenue minimum for 2016 of $70.0 million and quarterly OMIDRIA revenue minimums in 2017 and 2018, or maintain 50% of the then-outstanding note payable balance in restricted cash and certain eligible term investments. The Loan Agreement also includes provisions related to events of default, the occurrence of a material adverse effect and changes of control. The occurrence of an event of default could result in the acceleration of the Loan Agreement and, under certain circumstances, could increase our interest rate by 5.0% per annum during the period of default. There was no event of default under the Loan Agreement as of June 30, 2016.

As of June 30, 2016, the remaining unamortized discount and debt issuance costs associated with the debt were $5.1 million and $440,700, respectively.