Subsequent Events	12 Months Ended
Dec. 31, 2011
Subsequent Events	Note 14—Subsequent Events Lease Agreement On January 27, 2012, we entered into a lease with BMR-201 Elliott Avenue LLC, or the Landlord, for approximately 64,500 square feet of office and laboratory space in the building located at 201 Elliott Avenue West, Seattle, Washington, or The Omeros Building. The premises leased by us within The Omeros Building will replace the separate office and laboratory spaces that we currently occupy. The term of the lease is 15 years with two options to extend the lease term, each by 5 years. The expected term commencement date is October 1, 2012. The annual base rent due under the lease is $0 for the first year, $2.5 million for the second year and $3.2 million for the third year and will increase by 2.5% each year thereafter. In addition, we will be responsible for paying our proportionate share of utilities, taxes, insurance and maintenance as well as a property management fee. The Landlord has agreed to provide tenant improvements to the leased premises on a turn-key basis, a lease incentive (i.e., cash payment) to us of $3.0 million, and to reimburse us for up to $650,000 in expenses incurred by us in connection with The Omeros Building. The lease incentive is to be amortized over the initial Lease term at the annual rate of 3.0%. During the first three years of the lease term, we have the option to lease specified additional space in The Omeros Building. We have a right of first refusal for the remaining premises as well as a right of first offer for specified premises in The Omeros Building. If at any time during the term our space requirements exceed the available space in The Omeros Building, the Landlord will relocate us to a new building under a build-to-suit lease with no termination penalty payable under the Lease, subject to the negotiation of a mutually acceptable build-to-suit lease. In addition, beginning with the sixth year of the lease term, if we request from the Landlord additional space in The Omeros Building with a minimum square footage specified in the lease and the Landlord is unable to provide such additional space to us, we may terminate the lease without payment of any termination fees other than the unamortized lease incentive. We have the right to terminate the lease beginning with year nine of the Lease term, subject to the payment of a lease termination fee. If we terminate the lease during years 9 through 10, the termination fee is equal to 30% of the unamortized tenant improvements and 100% of the unamortized lease incentive. If we terminate the lease any time after year 10 of the term, the termination fee is equal to 20% of the unamortized tenant improvements and 100% of the unamortized lease incentive. On January 30, 2012, in connection with the new lease agreement for The Omeros Building, we gave notice to the landlord of our current corporate office space that we were terminating the lease for that space on January 30, 2013.

Note 14—Subsequent Events

Lease Agreement

On January 27, 2012, we entered into a lease with BMR-201 Elliott Avenue LLC, or the Landlord, for approximately 64,500 square feet of office and laboratory space in the building located at 201 Elliott Avenue West, Seattle, Washington, or The Omeros Building. The premises leased by us within The Omeros Building will replace the separate office and laboratory spaces that we currently occupy.

The term of the lease is 15 years with two options to extend the lease term, each by 5 years. The expected term commencement date is October 1, 2012. The annual base rent due under the lease is $0 for the first year, $2.5 million for the second year and $3.2 million for the third year and will increase by 2.5% each year thereafter. In addition, we will be responsible for paying our proportionate share of utilities, taxes, insurance and maintenance as well as a property management fee. The Landlord has agreed to provide tenant improvements to the leased premises on a turn-key basis, a lease incentive (i.e., cash payment) to us of $3.0 million, and to reimburse us for up to $650,000 in expenses incurred by us in connection with The Omeros Building. The lease incentive is to be amortized over the initial Lease term at the annual rate of 3.0%.

During the first three years of the lease term, we have the option to lease specified additional space in The Omeros Building. We have a right of first refusal for the remaining premises as well as a right of first offer for specified premises in The Omeros Building. If at any time during the term our space requirements exceed the available space in The Omeros Building, the Landlord will relocate us to a new building under a build-to-suit lease with no termination penalty payable under the Lease, subject to the negotiation of a mutually acceptable build-to-suit lease. In addition, beginning with the sixth year of the lease term, if we request from the Landlord additional space in The Omeros Building with a minimum square footage specified in the lease and the Landlord is unable to provide such additional space to us, we may terminate the lease without payment of any termination fees other than the unamortized lease incentive. We have the right to terminate the lease beginning with year nine of the Lease term, subject to the payment of a lease termination fee. If we terminate the lease during years 9 through 10, the termination fee is equal to 30% of the unamortized tenant improvements and 100% of the unamortized lease incentive. If we terminate the lease any time after year 10 of the term, the termination fee is equal to 20% of the unamortized tenant improvements and 100% of the unamortized lease incentive.

On January 30, 2012, in connection with the new lease agreement for The Omeros Building, we gave notice to the landlord of our current corporate office space that we were terminating the lease for that space on January 30, 2013.