Omeros (OMER) 10-K 15 Mar 16 2015 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2015	Mar. 07, 2016	Jun. 30, 2015
Document Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2015
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	FY
Trading Symbol	OMER
Entity Registrant Name	OMEROS CORP
Entity Central Index Key	1,285,819
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		38,257,381
Entity Public Float			$ 629,477,368

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 1,365	$ 354
Short-term investments	26,898	6,532
Receivables	6,517	392
Inventory	472	568
Prepaid Expense, Current	1,894	1,195
Total current assets	37,146	9,041
Property and equipment, net	951	782
Restricted Cash and Investments, Noncurrent	10,679
Restricted cash and investments		679
Other assets	219	332
Total assets	48,995	10,834
Current liabilities:
Accounts payable	6,428	4,915
Accrued expenses	9,752	7,070
Current portion of notes payable	73	6,330
Total current liabilities	16,253	18,315
Notes payable, net	49,769	26,123
Deferred rent	$ 9,207	$ 9,050
Commitments and contingencies (Note 9)
Shareholders’ deficit:
Preferred stock, par value $0.01 per share, 20,000,000 authorized and none issued at December 31, 2015 and 2014	$ 0	$ 0
Common stock, par value $0.01 per share, 150,000,000 shares authorized at December 31, 2015 and 2014; 38,040,891 and 34,185,464 issued and outstanding at December 31, 2015 and December 31, 2014, respectively.	380	342
Additional paid-in capital	376,528	285,050
Accumulated deficit	(403,142)	(328,046)
Total shareholders’ deficit	(26,234)	(42,654)
Total liabilities and shareholders’ deficit	$ 48,995	$ 10,834

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2015	Dec. 31, 2014
Preferred stock, par value (USD per share)	$ 0.01	$ 0.01
Preferred stock, authorized shares	20,000,000	20,000,000
Preferred stock, Issued shares	0	0
Preferred stock, outstanding shares	0	0
Common stock, par value (USD per share)	$ 0.01	$ 0.01
Common stock, authorized shares	150,000,000	150,000,000
Common stock, Issued shares	38,040,891	34,185,464
Common stock, outstanding shares	38,040,891	34,185,464

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Product Sales, Net	$ 13,264	$ 0	$ 0
Revenue from Grants	245	539	1,600
Grant revenue	13,509	539	1,600
Cost of Product Sales	1,041	0	0
Costs and expenses:
Research and development	48,379	47,946	36,297
Selling, general and administrative	35,327	22,601	15,819
Total costs and expenses	84,747	70,547	52,116
Loss from operations	(71,238)	(70,008)	(50,516)
Litigation settlement	0	0	12,500
Loss on early extinguishment of debt	(1,315)	0	0
Other income (expense), net	1,030	(195)	586
Interest expense	(3,573)	(3,470)	(2,366)
Net loss	(75,096)	(73,673)	(39,796)
Comprehensive loss	$ (75,096)	$ (73,673)	$ (39,796)
Basic and diluted net loss per share	$ (2)	$ (2.22)	$ (1.39)
Weighted-average shares used to compute basic and diluted net loss per share	37,560,257	33,234,294	28,560,360

CONSOLIDATED STATEMENTS OF SHAR

CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (DEFICIT) - USD ($)	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit
Balance (in shares) at Dec. 31, 2012		25,897,483
Balance at Dec. 31, 2012	$ (6,531,000)	$ 259,000	$ 207,787,000	$ (214,577,000)
Issuance of stock (in shares)		3,903,004
Issuance of stock	16,120,000	$ 39,000	16,081,000
Issuance of common stock utilizing At-The-Market Agreement, net of commissions		373,700
Issuance common stock utilizing At-The Market Agreement, net of commissions	4,868,000	$ 4,000	4,864,000
Issuance of common stock upon exercise of stock options for cash (in shares)		185,321
Issuance of common stock upon exercise of stock options for cash	662,000	$ 2,000	660,000
Stock-based compensation	6,252,000		6,252,000
Issuance of common stock warrants/warrant modification	41,000		41,000
Net loss	(39,796,000)			(39,796,000)
Balance (in shares) at Dec. 31, 2013		30,359,508
Balance at Dec. 31, 2013	(18,384,000)	$ 304,000	235,685,000	(254,373,000)
Issuance of stock (in shares)		3,500,000
Issuance of stock	37,754,000	$ 35,000	37,719,000
Issuance of common stock utilizing At-The-Market Agreement, net of commissions		28,653
Issuance common stock utilizing At-The Market Agreement, net of commissions	68,000	$ 0	68,000
Issuance of common stock upon exercise of stock options for cash (in shares)		297,303
Issuance of common stock upon exercise of stock options for cash	1,800,000	$ 3,000	1,797,000
Stock-based compensation	8,918,000		8,918,000
Issuance of common stock warrants/warrant modification	863,000		863,000
Net loss	(73,673,000)			(73,673,000)
Balance (in shares) at Dec. 31, 2014		34,185,464
Balance at Dec. 31, 2014	(42,654,000)	$ 342,000	285,050,000	(328,046,000)
Issuance of stock (in shares)		3,444,831
Issuance of stock	79,076,000	$ 34,000	79,042,000
Issuance of common stock utilizing At-The-Market Agreement, net of commissions		133,240
Issuance common stock utilizing At-The Market Agreement, net of commissions	$ 1,436,000	$ 1,000	1,435,000
Issuance of common stock upon exercise of stock options for cash (in shares)	277,356	277,356
Issuance of common stock upon exercise of stock options for cash	$ 1,423,000	$ 3,000	1,420,000
Stock-based compensation	9,581,000		9,581,000
Net loss	(75,096,000)			(75,096,000)
Balance (in shares) at Dec. 31, 2015		38,040,891
Balance at Dec. 31, 2015	$ (26,234,000)	$ 380,000	$ 376,528,000	$ (403,142,000)

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating activities:
Net loss	$ (75,096)	$ (73,673)	$ (39,796)
Adjustments to reconcile net loss to net cash used in operating activities:
Loss on early extinguishment of debt	1,315	0	0
Depreciation and amortization	209	317	302
Stock-based compensation expense	9,581	8,918	6,252
Non-cash interest expense	1,045	738	502
Warrant modification expense	0	863	41
Changes in operating assets and liabilities:
Receivables	(6,125)	(13)	1,555
Inventory	96	(568)	0
Prepaid expenses and noncurrent assets	(586)	(987)	84
Accounts payable and accrued expenses	4,195	5,459	(1,169)
Deferred revenue	0	0	(970)
Deferred rent	157	902	3,504
Net cash used in operating activities	(65,209)	(58,044)	(29,695)
Investing activities:
Purchases and sales of property and equipment, net	(240)	(28)	(204)
Purchases of investments	(91,766)	(58,849)	(47,182)
Proceeds from the sale and maturities of investments	71,400	65,034	55,295
Net cash provided by (used in) investing activities	(20,606)	6,157	7,909
Financing activities:
Proceeds from issuance of common stock and pre-funded warrants, net	79,076	37,754	20,988
Proceeds from borrowings under notes payable, net	22,329	12,699	0
Increase in restricted cash and investments	(10,000)	0	0
Repayments on notes payable	(7,438)	(1,464)	0
Proceeds upon exercise of stock options and warrants	2,859	1,868	662
Net cash provided by financing activities	86,826	50,857	21,650
Net increase (decrease) in cash and cash equivalents	1,011	(1,030)	(136)
Cash and cash equivalents at beginning of period	354	1,384	1,520
Cash and cash equivalents at end of period	1,365	354	1,384
Supplemental cash flow information
Cash paid for interest	4,236	2,674	1,709
Reduction of equipment cost basis due to assets purchased with grant funding	0	80	0
Property acquired under capital lease	$ 137	$ 200	$ 0

Organization and Basis of Prese

Organization and Basis of Presentation	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Organization and Basis of Presentation	Organization and Basis of Presentation Organization We are a biopharmaceutical company committed to discovering, developing and commercializing both small-molecule and protein therapeutics for large-market as well as orphan indications targeting inflammation, coagulopathies and disorders of the central nervous system. Our first drug product OMIDRIA has been approved by the United States (U.S.) Food and Drug Administration (FDA) for use during cataract surgery or intraocular lens (IOL) replacement. We broadly launched OMIDRIA in the U.S. in April 2015. Basis of Presentation Our consolidated financial statements include the financial position and results of operations of Omeros Corporation (Omeros) and our wholly owned subsidiaries. All inter-company transactions have been eliminated. The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (GAAP). Segments We operate in one segment. Management uses cash flow as the primary measure to manage our business and does not segment our business for internal reporting or decision-making. Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Significant items subject to such estimates include revenue recognition, stock-based compensation expense and accruals for clinical trials and contingencies. We base our estimates on historical experience and on various other factors that we believe are reasonable under the circumstances; however, actual results could differ from these estimates. Reclassifications Certain reclassifications have been made to prior periods in the consolidated financial statements and the accompanying notes to conform with the current presentation, none of which impacted our net loss or working capital. Liquidity and Capital Resources We generated net losses of $75.1 million , $73.7 million and $39.8 million in 2015 , 2014 and 2013 , respectively, and as of December 31, 2015 , we had $28.3 million in cash, cash equivalents and short-term investments available for general corporate use. In addition, in restricted cash and investments we have $10 million that must be maintained in depository and investment accounts pursuant to the new Loan and Security Agreement (the Oxford/EWB Loan Agreement) with Oxford and EastWest Bank (EWB) as well as $679,000 used to secure a letter of credit for the Omeros Building lease. We expect to continue to incur losses until such time as OMIDRIA product sales, corporate partnerships and/or licensing revenues from products or programs are adequate to support our ongoing operating expenses and debt service. We are unable to predict if or when this may occur, and until it does occur, we will need to continue to raise additional funds through public or private equity securities sales including our ATM with JonesTrading (see Note 10 for further detail), through the issuance of additional debt, through corporate partnerships, through asset sales or through the pursuit of collaborations and licensing arrangements related to certain of our products or programs. These conditions raise a substantial doubt about our ability to continue as a going concern. If we are unable to become cash-flow positive or to raise additional capital as and when needed, or upon acceptable terms, such failure would have a significant negative impact on our financial condition. The accompanying consolidated financial statements have been prepared on a going-concern basis, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business. The accompanying consolidated financial statements do not include any adjustments to reflect the possible future effects on the recoverability and classification of assets or the amounts and classification of liabilities that may result from uncertainty related to our ability to continue as a going concern.

Significant Accounting Policies

Significant Accounting Policies (Notes)	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Significant Accounting Policies	Significant Accounting Policies Cash and Cash Equivalents, Short-Term Investments, and Restricted Cash and Investments Cash and cash equivalents include highly liquid investments with a maturity of three months or less on the date of purchase. Short-term investment securities are classified as available-for-sale and are carried at fair value. Unrealized gains and losses, if any, are reported as a separate component of shareholders’ deficit. Amortization, accretion, interest and dividends, realized gains and losses and declines in value judged to be other-than-temporary are included in other income (expense). The cost of securities sold is based on the specific-identification method. Investments in securities with maturities of less than one year, or those for which management intends to use the investments to fund current operations, are included in current assets. We evaluate whether an investment is other-than-temporarily impaired based on the specific facts and circumstances. Factors that are considered in determining whether an other-than-temporary decline in value has occurred include: the market value of the security in relation to its cost basis; the financial condition of the investee; and the intent and ability to retain the investment for a sufficient period of time to allow for recovery in the market value of the investment. Restricted cash and investments are held in certificates of deposit and money-market funds. Inventory Inventory is stated at the lower of cost or market determined on a specific identification basis in a manner which approximates the first-in, first-out (FIFO) method. Costs include amounts related to third party manufacturing, transportation and internal labor and overhead. Capitalization of costs as inventory begins when the product candidate receives regulatory approval in the U.S. or the European Union (EU), which for OMIDRIA began upon U.S. regulatory approval in May 2014. We expense inventory costs related to product candidates as research and development expenses prior to receiving regulatory approval in the respective territory. Inventory is reduced to net realizable value for excess and obsolete inventories based on forecasted demand. Receivables Receivables relate primarily to sales of OMIDRIA to wholesalers and include reductions for estimated chargebacks, rebates, and product returns which are expected to be settled through reductions in receivables. Remaining receivables consist of amounts related to grants from the National Institutes of Health (NIH) and subleases for space in The Omeros Building. Considering the nature and historic collectability of our receivables, we concluded an allowance for doubtful accounts is not necessary as of December 31, 2015 and 2014 . Property and Equipment, net Property and equipment are stated at cost and depreciation is calculated using the straight-line method over the estimated useful life of the assets, which is generally three to ten years. Equipment financed under capital leases is recorded as property and equipment and is amortized over the shorter of the useful lives of the related assets or the lease term. Expenditures for equipment purchased with grant funds are recorded as a reduction to the cost of the applicable equipment. Expenditures for repairs and maintenance are expensed as incurred. Impairment of Long-Lived Assets The carrying amount of long-lived assets is reviewed whenever events or changes in circumstances indicate that the carrying value of an asset may not be recoverable. Recoverability of these assets is measured by comparing the carrying value to future undiscounted cash flows the asset is expected to generate. If the asset is considered to be impaired, the amount of any impairment will be reflected in the results of operations in the period of impairment. We have not recognized any impairment losses for the years ending December 31, 2015 , 2014 and 2013 . Deferred Rent We recognize rent expense on a straight-line basis over the noncancelable term of The Omeros Building operating lease and, accordingly, record the difference between cash rent payments and the recognition of rent expense as an increase or decrease in deferred rent liability. We also record landlord-funded lease incentives, such as reimbursable leasehold improvements, as an increase in deferred rent liability which is amortized as a reduction of rent expense over the noncancelable terms of The Omeros Building operating lease. Revenue Recognition Our revenues are comprised of product sales of OMIDRIA and amounts earned for services under grants from third parties. Revenue is recognized when there is persuasive evidence that an arrangement exists, product title and risk of loss is passed to the customer or the service has been provided, the price is fixed or determinable and collection is reasonably assured. Product Sales, Net We record revenue from product sales when the product is delivered to our wholesalers. Product sales to a wholesaler are not recorded if we determine that the wholesaler’s on-hand OMIDRIA inventory, based on inventory information we regularly receive from our wholesalers, exceeds approximately eight weeks of projected demand. Product sales are recorded net of chargebacks and rebates, wholesaler distribution fees and estimated product returns. Accruals or allowances are established for these deductions when revenue is recognized, and actual amounts incurred are offset against the applicable accruals or allowances. We reflect each of these accruals or allowances as either a reduction in the related account receivable or as an accrued liability, depending on how the amount is settled. Provisions for chargebacks are determined utilizing historical and projected payer mix and sale-through and inventory on-hand information received directly from wholesalers. Chargebacks are generally settled within four weeks of recording product sales revenue. We provide reimbursement support services and financial assistance in the form of a rebate to patients whose commercial insurance is inadequate to cover the full cost of OMIDRIA. We apply an experience ratio to product sales to determine the rebate accrual. This experience ratio is reviewed and updated periodically to reflect actual results. We allow for the return of product up to 12 months past its expiration date or for product that is damaged. In estimating product returns, we take into consideration our single-tier distribution model, our expectation that product is typically not held by the healthcare providers based on the frequency of their reorders, inventory in the wholesale channel, our return experience to date, the remaining shelf life of product we have previously sold and historical industry return rates. We pay our wholesalers a distribution fee for services they perform on our behalf based on a contractual rate. Research and Development Research and development costs are comprised primarily of costs for personnel, including salaries, benefits and stock compensation; an allocation of our occupancy costs; clinical study costs; contracted research; manufacturing; consulting arrangements; depreciation; materials and supplies; milestones; and other expenses incurred to sustain our overall research and development programs. Research and development costs are expensed as incurred. Advance payments for goods or services that will be used or rendered for future research and development activities are deferred and then recognized as an expense as the related goods are delivered or the services are performed, or when the goods or services are no longer expected to be provided. Patents We generally apply for patent protection on processes and product candidates we or our licensors conceive or develop. Patent costs are comprised primarily of external legal fees, filing fees incurred to file patent applications, and periodic renewal fees to keep the patent in force and are expensed as incurred as a component of general and administrative expense. Selling, General and Administrative Selling, general and administrative (SG&A) expenses are comprised primarily of salaries, service fees incurred for our dedicated contracted sales force, benefits, and stock-compensation costs for sales, marketing, and other personnel not directly engaged in research and development. Additionally, SG&A includes marketing and selling expenses, professional and legal services; patent costs; depreciation, an allocation of our occupancy costs; and other general corporate expenses. Effective January 1, 2016, we converted our dedicated contracted sales force provided by a third party to Omeros employees. Advertising Advertising costs, which we consider to be media and marketing materials, are expensed as incurred. We incurred $ 885,000 in advertising expense during the year ended December 31, 2015 . We had no similar expenses during the years ended December 31, 2014 and 2013 , respectively. Income Taxes Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their tax bases. Deferred tax assets and liabilities are measured using enacted tax rates applied to taxable income in the years in which those temporary differences are expected to be recovered or settled. We recognize the effect of income tax positions only if those positions are more likely than not of being sustained upon an examination. A valuation allowance is established when it is more likely than not that the deferred tax assets will not be realized. Stock-Based Compensation Stock-based compensation expense is recognized for all share-based payments made to employees, directors and non-employees based on estimated fair values. The fair value of our stock options is calculated using the Black-Scholes option-pricing model which requires judgmental assumptions including volatility, forfeiture rates and expected option life. We use the straight-line method to allocate compensation cost to reporting periods over each optionee’s requisite service period for employees and directors, which is generally the vesting period. Stock options granted to non-employees are accounted for using the fair-value approach and are subject to periodic revaluation over their vesting terms as earned. Accumulated Other Comprehensive Loss Accumulated other comprehensive loss is comprised of net loss and certain changes in equity that are excluded from net loss. There was no difference between comprehensive loss and net loss for the years ended December 31, 2015 , 2014 or 2013 . Financial Instruments and Concentrations of Credit Risk Cash and cash equivalents, receivables, accounts payable and accrued liabilities, which are recorded at invoiced amount or cost, approximate fair value based on the short-term nature of these financial instruments. The fair value of short-term investments is based on quoted market prices. Financial instruments that potentially subject us to concentrations of credit risk consist primarily of cash and cash equivalents, short-term investments and receivables. Cash and cash equivalents are held by financial institutions and are federally insured up to certain limits. At times, our cash and cash equivalents balance exceeds the federally insured limits. To limit the credit risk, we invest our excess cash in high quality securities such as money market mutual funds, certificates of deposit and commercial paper. Major Customers We sell OMIDRIA through a limited number of wholesalers. Each of these wholesalers, together with entities under their common control, accounted for greater than 10% of total revenues for the year ended December 31, 2015 and greater than 10% of accounts receivable as of December 31, 2015 as noted below. Percentage of Total Revenue Percentage of Accounts Receivable Distributor A 37% 45% Distributor B 31% 23% Distributor C 28% 27% Major Suppliers We use a small number of contract manufacturers to supply OMIDRIA and to produce clinical trial material which creates a concentration of risk for us. With regards to OMIDRIA, Patheon Manufacturing Services, LLC (Patheon) is completing the analytical testing required before transferring OMIDRIA commercial product, costing $1.3 million , to us. We anticipate receiving the product during the first quarter of 2016 and the product dating will allow the product to be sold through at least the third quarter of 2018. This is the final commercial supply of OMIDRIA that Patheon will be available to produce using Patheon’s facility currently approved for manufacturing OMIDRIA. We have entered into a non-exclusive agreement with Hospira Worldwide, Inc. (Hospira) for the ongoing commercial supply of OMIDRIA and we are currently completing the manufacturing process transfer, process validation and approval of Hospira as a manufacturing site for OMIDRIA. We anticipate Hospira will be able to provide OMIDRIA commercial product to us beginning in 2017. We believe the commercial supply of OMIDRIA currently undergoing final analytical testing at Patheon plus our OMIDRIA inventory on hand will be adequate to supply our needs of OMIDRIA until Hospira is able to supply our OMIDRIA commercial product needs. While one source of supply is utilized for OMIDRIA and generally one source for each of our product candidates, other sources are available should we need to change suppliers. We endeavor to maintain reasonable levels of drug supply for our commercial and clinical trial use. A change in suppliers, however, could cause a delay in delivery of OMIDRIA or our clinical trial material that would adversely affect our business. Recently Adopted Accounting Pronouncements For the year ended December 31, 2015 we adopted and applied retrospectively Financial Accounting Standards Board (FASB) Accounting Standards Update, or ASU, No. 2015-03, related to simplifying the presentation of debt issuance costs. This standard requires debt issuance costs related to a recognized debt liability to be presented in the balance sheet as a direct deduction to the liability. The adoption of ASU 2015-03 resulted in the reclassification of $300,000 of debt issuance costs from Other Current Assets and Other Assets to Current Portion of Notes Payable and Notes Payable in our December 31, 2014 Consolidated Balance Sheet. In November 2015, FASB issued ASU, No. 2015-17 that simplifies the presentation of deferred tax assets and liabilities by jurisdiction, along with any related valuation allowance. The new guidance requires companies to classify all deferred tax assets and liabilities as noncurrent on the balance sheet. We have elected to apply this standard prospectively for the year ended December 31, 2015. As we have a full valuation allowance against our deferred tax assets for all periods presented, the adoption had no material impact on the presentation of our financial condition, results of operations, cash flow and financial statement disclosures. Recent Accounting Pronouncements In February 2016, FASB issued ASU 2016-02 related to lease accounting. This standard requires lessees to recognize a right-of-use asset and a lease liability for most leases. This standard must be applied using a modified retrospective transition and is effective for all annual and interim periods beginning after December 15, 2018. Earlier adoption is permitted. We are evaluating how this new standard will impact the presentation of our financial statements and related disclosures. In July 2015, FASB issued ASU 2015-11 related to simplifying the measurement of inventory. This standard requires inventory to be measured at the lower of cost or net realizable value. This standard must be applied prospectively and is effective for all annual and interim periods beginning after December 15, 2016. Earlier application is permitted as of the beginning of an interim or annual reporting period. This standard is not expected to have a material impact on the presentation of the our financial position. In August 2014, FASB issued ASU No. 2014-15 related to disclosure of an entity’s ability to continue as a going concern. This standard requires management to evaluate whether substantial doubt exists regarding the entity’s ability to continue as a going concern at each reporting period for a duration of one year after the date the financial statements are issued or available to be issued. The standard establishes certain required disclosures if substantial doubt exists. This standard must be applied prospectively and is effective for interim and annual periods beginning after December 15, 2016. We will review the impact of the standard upon our disclosures, if applicable, beginning in 2017. In May 2014, FASB issued ASU No. 2014-09 related to the recognition of revenue that supersedes existing guidance. This standard clarifies the principles for recognizing revenue utilizing a five-step process. This standard must be applied retroactively to each prior reporting period presented, or retrospectively with the cumulative effect of applying the standard recognized in the period adopted. As amended, the standard is effective for interim and annual periods beginning after December 15, 2017 and cannot be adopted before that effective date. We are currently evaluating the impact that this standard may have on our financial statements once it is adopted.

Net Loss Per Share

Net Loss Per Share	12 Months Ended
	Dec. 31, 2015
Earnings Per Share [Abstract]
Net Loss Per Share	Net Loss Per Share Basic net loss per share is calculated by dividing the net loss by the weighted-average number of common shares outstanding for the period. Diluted net loss per share is computed by dividing the net loss by the weighted-average number of common shares and dilutive common share equivalents outstanding for the period, determined using the treasury-stock method. The basic and diluted net loss per share amounts for the years ended December 31, 2015 , 2014 and 2013 were computed based on the shares of common stock outstanding during the respective periods. Potentially dilutive securities excluded from the diluted loss per share calculation are as follows: Year Ended December 31, 2015 2014 2013 Outstanding options to purchase common stock 8,310,235 8,364,469 6,969,303 Warrants and pre-funded warrants to purchase common stock 749,250 551,435 609,016 Total potentially dilutive securities 9,059,485 8,915,904 7,578,319

Cash, Cash Equivalents and Inve

Cash, Cash Equivalents and Investments	12 Months Ended
	Dec. 31, 2015
Cash and Cash Equivalents [Abstract]
Cash, Cash Equivalents and Investments	Cash, Cash Equivalents and Investments As of December 31, 2015 and 2014 , all investments are classified as short-term and available-for-sale on the accompanying Consolidated Balance Sheets. We did not own any securities with unrealized loss positions as of December 31, 2015 or 2014 . Investment income, which is included as a component of other income (expense), consists primarily of interest earned.

Fair-Value Measurements

Fair-Value Measurements	12 Months Ended
	Dec. 31, 2015
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair-Value Measurements On a recurring basis, we measure certain financial assets at fair value. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability, an exit price, in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The accounting standard establishes a fair value hierarchy that requires an entity to maximize the use of observable inputs, where available. The following summarizes the three levels of inputs required: Level 1—Observable inputs for identical assets or liabilities, such as quoted prices in active markets; Level 2—Inputs other than quoted prices in active markets that are either directly or indirectly observable; and Level 3—Unobservable inputs in which little or no market data exists, therefore they are developed using estimates and assumptions developed by us, which reflect those that a market participant would use. Our fair-value hierarchy for our financial assets and liabilities measured at fair value on a recurring basis are as follows: December 31, 2015 Level 1 Level 2 Level 3 Total (In thousands) Assets: Money-market funds classified as non-current restricted cash and investments $ 10,679 $ — $ — $ 10,679 Money-market funds classified as short-term investments 26,898 — — 26,898 Total $ 37,577 $ — $ — $ 37,577 December 31, 2014 Level 1 Level 2 Level 3 Total (In thousands) Assets: Money-market funds classified as non-current restricted cash and investments $ 679 $ — $ — $ 679 Money-market funds classified as short-term investments 6,532 — — 6,532 Total $ 7,211 $ — $ — $ 7,211 Cash held in demand deposit accounts of $1.4 million and $354,000 is excluded from our fair-value hierarchy disclosure as of December 31, 2015 and 2014 , respectively. There were no unrealized gains and losses associated with our short-term investments as of December 31, 2015 or 2014 . The carrying amounts reported in the accompanying Consolidated Balance Sheets for receivables, accounts payable and other current monetary assets and liabilities approximate fair value because of the immediate or short-term maturity of these financial instruments.

Certain Balance Sheet Accounts

Certain Balance Sheet Accounts	12 Months Ended
	Dec. 31, 2015
Balance Sheet Related Disclosures [Abstract]
Certain Balance Sheet Accounts	Certain Balance Sheet Accounts Receivables December 31, 2015 2014 (In thousands) Trade receivables, net $ 6,208 $ — Grant receivables 136 324 Other receivables 173 68 Total receivables $ 6,517 $ 392 Trade accounts receivable are shown net of $191,000 of chargebacks and product return allowances as of December 31, 2015. Inventory December 31, 2015 2014 (In thousands) Raw materials $ 93 $ — Work-in-process 158 — Finished goods 221 568 Total inventory $ 472 $ 568 Property and Equipment December 31, 2015 2014 (In thousands) Laboratory equipment $ 1,735 $ 1,636 Office equipment and furniture 625 615 Computer equipment 482 403 Capital lease equipment 367 230 Computer software 174 126 Total cost 3,383 3,010 Less accumulated depreciation and amortization (2,432 ) (2,228 ) Total property and equipment, net $ 951 $ 782 For the years ended December 31, 2015 , 2014 and 2013 , depreciation and amortization expense was $209,000 , $317,000 and $302,000 , respectively. Accrued Expenses December 31, 2015 2014 (In thousands) Contract research and development $ 2,973 $ 1,280 Employee compensation 2,590 2,421 Consulting and professional fees 2,400 1,952 Clinical trials 1,108 828 Other accruals 681 589 Total accrued liabilities $ 9,752 $ 7,070

Notes Payable NotesPayable (Not

Notes Payable NotesPayable (Notes)	12 Months Ended
	Dec. 31, 2015
Debt Disclosure [Abstract]
Notes Payable	Notes Payable Loan and Security Agreement In October 2010, we entered into a loan and security agreement (the Oxford Loan Agreement) with Oxford Finance LLC (Oxford). In December 2012 we amended the Oxford Loan Agreement and increased the outstanding principal balance to $20.0 million . The Oxford Loan Agreement provided for interest-only payments at an annual rate of 9.25% through December 31, 2013 with principal and interest payments commencing January 1, 2014. In connection with the Oxford Loan Agreement, we agreed to pay Oxford $1.4 million in a loan maturity fee that was being amortized to interest expense using the effective-interest method. In March 2014, we entered into a Loan and Security Agreement (the Oxford/MidCap Loan Agreement) with Oxford and MidCap Financial SBIC, LP (MidCap) pursuant to which we borrowed $32.0 million . We used $19.1 million of the loan proceeds to repay all of the amounts owed by us under our then outstanding Oxford Loan Agreement from Oxford and, after deducting loan initiation costs, we received $12.7 million in net proceeds. The Oxford/MidCap Loan Agreement provided for interest-only payments at an annual rate of 9.25% through March 1, 2015 with principal and interest payments of $1.0 million commencing April 1, 2015 through its maturity date of March 1, 2018. In addition, the Oxford/MidCap Loan Agreement required a $2.2 million loan maturity fee payment upon full repayment of the loan and a prepayment fee equal to 1.0% of the then-outstanding principal balance if we paid the loan prior to the maturity date. We accounted for the Oxford/MidCap Loan Agreement as a debt modification and, accordingly, the unamortized debt issuance costs associated with the then-outstanding loan with Oxford, and the debt issuance costs associated with the Oxford/MidCap Loan Agreement were being amortized to interest expense using the effective interest method over the remaining term of Oxford/MidCap Loan Agreement. Additionally, the loan maturity fee, which was treated as a debt discount, was being amortized to interest expense using the effective-interest method. In December 2015, we entered into a new Loan and Security Agreement (the Oxford/EWB Loan Agreement) with Oxford and East West Bank (EWB) pursuant to which we borrowed $50.0 million . In addition, under the Oxford/EWB Loan Agreement we can borrow an additional $20.0 million in two tranches of $10.0 million each through June 30, 2017, contingent upon the satisfaction of certain conditions including minimum net revenues from OMIDRIA. We used $27.3 million of the loan proceeds to repay all of the amounts owed by us under our then-outstanding Oxford/Midcap Loan Agreement including the outstanding principal of $24.8 million , the loan maturity fee of $2.2 million and the prepayment fee of $248,000 . After deducting all loan initiation and outstanding interest on the Oxford/MidCap Loan Agreement, we received $22.3 million in net proceeds. We accounted for the termination of the Oxford/Midcap Loan Agreement as a debt extinguishment and, accordingly, incurred a loss of $1.3 million associated with the unamortized loan maturity fee and the prepayment fee. The Oxford/EWB Loan Agreement requires monthly interest-only payments of $385,000 on the original $50.0 million we borrowed computed at an annual rate of 9.25% through July 1, 2017. Beginning August 1, 2017, monthly principal and interest payments of approximately $1.9 million are due on the original $50.0 million we borrowed through the maturity date of January 1, 2020. In addition, the Oxford/EWB Loan Agreement requires a $3.8 million loan maturity fee upon full repayment of the initial $50.0 million borrowed and $525,000 for each additional $10.0 million borrowed. We may prepay the outstanding principal balance in its entirety at any time if we pay a prepayment equal to 1.0% of the then-outstanding principal balance. As security under the Oxford/EWB Loan Agreement, we granted Oxford, as collateral agent for the lenders, a security interest in substantially all of our assets, excluding intellectual property (other than proceeds derived from any intellectual property). The Oxford/EWB Loan Agreement contains covenants that require us to maintain $10.0 million in restricted cash and certain eligible term investments, meet an annual OMIDRIA revenue minimum for 2016 and quarterly OMIDRIA revenue minimums in 2017 and 2018, and to establish an at-the-market (ATM) equity facility that we established on January 6, 2016 (see Note 10). The Oxford/EWB Loan Agreement also contains covenants that limit or restrict our ability to incur indebtedness, grant liens, merge or consolidate, dispose of assets, make investments, make acquisitions, enter into certain transactions with affiliates, pay dividends or make distributions, repurchase stock, license our intellectual property for a limited set of our programs without lender approval or pledge our intellectual property. Additionally, the Oxford/EWB Loan Agreement includes events of default regarding non-payment, inaccuracy of representations and warranties, covenant breaches, occurrence of a material adverse effect (MAE, as defined below), cross default to material indebtedness, bankruptcy or insolvency, material judgments, and a change of control. The occurrence of an event of default could result in the acceleration of the Oxford/EWB Loan Agreement and, under certain circumstances, could increase our interest rate by 5.0% per annum during the period of default. MAE is defined as a material adverse effect upon (i) our business operations, properties, assets, results of operations or financial condition of Omeros, taken as a whole with respect to our viability, that reasonably would be expected to result in our inability to repay any portion of the loans in accordance with the terms of the Oxford/EWB Loan Agreement, (ii) the validity, perfection, value or priority of the lenders’ security interest in the collateral, (iii) the enforceability of any material provision of the Oxford/EWB Loan Agreement or related agreements, or (iv) the ability of the lenders to enforce their rights and remedies under the Oxford/EWB Loan Agreement or related agreements. As of December 31, 2015, the outstanding principal on the Oxford/EWB Loan Agreement was $50.0 million and the remaining unamortized discount and debt issuance costs were $3.8 million and $436,000 , respectively. Additionally, there were no covenant violations during the year ended December 31, 2015. Equipment Financing We have capital leases for certain lab and office equipment which have lease terms expiring between October 2017 and June 2019 . Equipment costs related to these capital leases of $367,000 and $230,000 is included in our property and equipment as of December 31, 2015 and December 31, 2014 , respectively and the accumulated depreciation on this equipment was $98,000 and $52,000 , respectively. The remaining principal payments under these capital leases totaled $281,000 and $185,000 as of December 31, 2015 and 2014 , respectively. Future Principal Payments Future principal payments as of December 31, 2015 under the Oxford/EWB Loan Agreement and our capital equipment financing leases, based on stated contractual maturities, are as follows: Year Ending December 31, Total (In thousands) 2016 $ 73 2017 7,627 2018 19,432 2019 21,258 2020 1,891 Total future principal payments $ 50,281 The principal payments reflected in the table above exclude the $436,000 unamortized balance of the debt discount.

Revenue

Revenue	12 Months Ended
	Dec. 31, 2015
Revenue Recognition [Abstract]
Revenue	Revenue Revenues recognized from grants are as follows: Year Ended December 31, 2015 2014 2013 (In thousands) Small Business Innovative Research Grants (SBIR) $ 245 $ 539 $ 630 Vulcan Inc. — — 970 Total revenue $ 245 $ 539 $ 1,600 We have periodically received Small Business Innovative Research (SBIR) grants from the National Institutes of Health (NIH) which are used to support the research and development of our product candidates. We recorded revenue related to these grants of $245,000 , $539,000 and $630,000 for the years ended December 31, 2015 , 2014 and 2013 , respectively. We recorded cost reductions to property and equipment due to assets being purchased with grant funding of $80,000 for the year ended December 31, 2014 . We had no similar cost reductions to property and equipment for the years ended December 31, 2015 and 2013. As of December 31, 2015 , $219,000 of potential revenue remained available under these grants, if qualifying research is performed. In 2010, we entered into a platform development funding agreement with Vulcan Inc. and its affiliate (collectively, Vulcan) pursuant to which we received $20.0 million for our G protein-coupled receptor (GPCR) program. The revenue was recognized as costs were incurred or as a reduction to the costs of assets purchased in direct proportion to the related GPCR expenses. For the year ended December 31, 2013, we recognized all the remaining revenue of $970,000 from this funding agreement.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Real Estate and Equipment Lease Obligations We lease office and laboratory spaces in The Omeros Building. The initial term of this lease ends in November 2027 and we have two options to extend the lease term, each by five years. As of December 31, 2015 , the remaining aggregate non-cancelable rent under the initial terms of the lease was $54.5 million . The deferred rent balance of $9.2 million relates to rent deferrals and landlord funded lease incentives since the inception of our lease and is being amortized to research and development and selling, general and administrative expense on a straight-line basis through the initial term of the lease. Rent expense, including the amortization of lease incentives and rent deferrals, totaled $4.5 million , $4.5 million and $4.3 million for the years ended December 31, 2015 , 2014 and 2013 , respectively. We periodically sublease unused office and laboratory space in The Omeros Building to third-party tenants. Rental income received under these subleases was $889,000 , $568,000 and $550,000 for the years ended December 31, 2015 , 2014 and 2013 , respectively. Rental income is recorded as other income in the accompanying Consolidated Statements of Operations and Comprehensive Loss. We rent equipment under various operating lease agreements which have remaining aggregate non-cancellable rent of $76,000 at December 31, 2015. Future minimum payments related to these leases and The Omeros Building lease, which exclude common area maintenance and related operating expenses, at December 31, 2015 , are as follows: Year Ending December 31, Lease Sublease Net Lease (In thousands) 2016 $ 4,106 $ 682 $ 3,424 2017 4,188 580 3,608 2018 4,259 — 4,259 2019 4,350 — 4,350 2020 4,450 — 4,450 Thereafter 33,263 — 33,263 Total $ 54,616 $ 1,262 $ 53,354 Contracts As of December 31, 2015, we have a firm purchase commitment with Patheon for the manufacture of $1.3 million of commercial supply of OMIDRIA. We anticipate receiving the product during the first quarter of 2016. Development Milestones and Product Royalties Phosphodiesterase 10 (PDE10) inhibitors - In connection with a funding agreement with The Stanley Medical Research Institute entered into in December 2006, beginning the first calendar year after commercial sales of any therapeutic product that inhibits or modulates PDE10 (including for schizophrenia or Huntington’s disease), we are obligated to pay royalties based on net income of the product, as defined in the agreement. Based on the amount of grant funding received, the maximum amount of royalties payable by us is $12.8 million . For the years ended December 31, 2015 , 2014 and 2013 , we did not owe any royalties. Peroxisome proliferators activated receptor gamma (PPARγ) - In February 2009, we entered into a patent assignment agreement whereby we acquired all intellectual property rights, including patent applications, related to PPARγ agonists for the treatment and prevention of addictions to substances of abuse, as well as other compulsive behaviors. In February 2011, we amended the patent assignment agreement to include all intellectual property rights, including patent applications, related to dietary supplements that increase PPARγ activity. We will be required to make payments up to $3.8 million in total, for both PPARγ agonists and dietary supplements that increase PPARγ activity, upon achievement of certain development events, such as the initiation of clinical trials and receipt of marketing approval. In addition, we are obligated to pay a low single-digit percentage royalty on any net sales of drug products that are covered by the patent assignment agreement. For the years ended December 31, 2015 , 2014 and 2013 , we did not owe any development milestones or royalties. Phosphodiesterase 7 (PDE7) inhibitors - Under a license agreement with Daiichi Sankyo Co., Ltd. (Daiichi Sankyo) we hold an exclusive license to phosphodiesterase 7 (PDE7) inhibitors owned by Daiichi Sankyo for use in (1) the treatment of movement disorders and other specified indications; (2) addiction and compulsive disorders; and (3) all other indications except those related to dermatologic conditions. We will be required to make milestone payments to Daiichi Sankyo of up to $33.5 million upon the achievement of certain events, such as successful completion of certain preclinical toxicology studies; dosing of human subjects in Phase 1, 2 and 3 clinical trials; receipt of marketing approval of a PDE7 inhibitor product; and reaching specified sales milestones. However, if only one of the three indications is advanced through each milestone, the total milestone payments would be $23.5 million . In addition, we are obligated to pay Daiichi Sankyo a low single-digit percentage royalty on any net sales of a PDE7 inhibitor licensed under the agreement provided that if the sales are made by a sublicensee, the amount payable by us to Daiichi Sankyo is capped at a low double-digit percentage of all royalty and specified milestone payments that we receive from the sublicensee. For the year ended December 31, 2013, we paid $50,000 upon execution of an amendment which was recognized as research and development expense. For the years ended December 31, 2015 , 2014 and 2013 , we did not owe any development milestones or royalties. Mannan-binding lectin-associated serine protease-2 (MASP-2) - In April 2010, we entered into an exclusive license agreement with Helion Biotech ApS (Helion), pursuant to which we received a royalty bearing, worldwide exclusive license to all of Helion’s intellectual property rights related to MASP-2 antibodies, polypeptides and methods in the field of inhibition of mannan-binding lectin-mediated activation of the complement system for the prevention, treatment or diagnosis of any disease or condition. We will be required to make development and sales milestone payments to Helion of up to $6.1 million upon the achievement of certain events, such as the filing of an Investigational New Drug Application (IND) with the FDA; initiation of Phase 2 and 3 clinical trials; receipt of marketing approval; and reaching specified sales milestones. We are obligated to pay Helion a low single-digit percentage royalty on net sales of a MASP-2 inhibitor product covered by the patents licensed under the agreement. For the year ended December 31, 2015 , we did not owe any development milestones or royalties. For the years ended December 31, 2014 and 2013 , we incurred development milestone costs of $300,000 and $200,000 , respectively, under this agreement which was recognized as research and development expense. G protein-coupled receptor (GPCR) - In connection with our funding agreements with Vulcan and LSDF discussed in Note 8, we agreed to pay Vulcan and LSDF tiered percentages of the net proceeds derived from the GPCR program. The percentage rates decrease as the cumulative net proceeds reach specified thresholds, and the blended percentage rate in the aggregate is in the mid-teens with respect to approximately the first $1.5 billion of cumulative net proceeds. If we receive cumulative net proceeds in excess of approximately $1.5 billion , the percentage rate decreases to one percent. Pursuant to the agreement with Vulcan, we may pay a portion of Vulcan’s share of the one percent of net proceeds to a life sciences initiative (LSI) to be established in accordance with the LSDF agreement. The LSI will be a non-profit, tax-exempt organization with a mission to advance life sciences in the State of Washington. Net proceeds are generally defined in the Vulcan and LSDF agreements as (1) all consideration received by us in any form relating directly to the GPCR program less (2) all expenses and expenditures in excess of $25.0 million incurred by us in connection with the GPCR program. Any consideration that we receive (a) from government entities (subject to specified exceptions), (b) from third parties that have designated such consideration for the purpose of funding research and development expenses and related overhead or (c) in the form of grants, as well as any expenses or expenditures that we incur that are paid for with such consideration, are excluded for purposes of determining net proceeds. Under our agreement with Vulcan, we granted Vulcan a security interest in our personal property related to the GPCR program, other than intellectual property, which security interest is junior to any existing or future security interests granted in connection with a financing transaction and which will be automatically released after Vulcan receives $25.0 million under the agreement. We also agreed not to grant any liens on intellectual property related to the GPCR program. The term of our agreement with Vulcan is 35 years , provided that the term will automatically extend until the cumulative net proceeds that we receive from the GPCR program are approximately $1.5 billion . Under our agreement with LSDF, after LSDF receives $25.0 million , any remaining amounts that would be payable to LSDF will be paid to LSI. Our obligations with respect to LSI are limited to creating LSI’s charter documents, incorporating LSI, selecting directors and applying for tax exempt status, all in consultation with LSDF. The term of our agreement with LSDF expires on the six-month anniversary following the last date that we deliver a report related to our incurrence of grant-funded expenses described in the agreement. The term of our payment obligations to LSDF is the same as that under our agreement with Vulcan. As of December 31, 2015 , we have not derived any net proceeds as defined in the Vulcan and LSDF agreements from our GPCR program. Litigation In July 2015, we received a Notice Letter from Par Pharmaceutical, Inc. and its subsidiary, Par Sterile Products, LLC, (collectively, Par) stating that Par filed an Abbreviated New Drug Application (ANDA) containing a Paragraph IV Certification under the Hatch-Waxman Act seeking approval from the FDA to market a generic version of OMIDRIA prior to the expiration of three patents listed in the FDA’s Approved Drug Products with Therapeutic Equivalence Evaluations (Orange Book) for OMIDRIA (the Orange Book Patents). Following receipt of the Paragraph IV Notice Letter, in September 2015 we filed a patent infringement lawsuit under the Hatch-Waxman Act against Par in the U.S. District Court for the District of New Jersey and in the U.S. District Court for the District of Delaware. Based on our decision to pursue the action in federal court in Delaware, we voluntarily dismissed the complaint filed in the U.S. District Court for the District of New Jersey. The complaint that we filed in the U.S. District Court for the District of Delaware has been served on Par and Par has filed an answer asserting defenses and counterclaims for declaratory judgment of patent invalidity and non-infringement. We intend to seek leave to amend the lawsuit to assert a fourth patent, that issued after Par’s Notice Letter, and which was granted by the U.S. Patent and Trademark Office (USPTO) after the USPTO considered all alleged prior art that was identified by Par in its Paragraph IV Notice Letter. The filing of suit against Par triggered a 30-month stay of the FDA’s approval of Par’s ANDA, which is expected to remain in effect until late January 2018. We have reviewed the assertions in Par’s Paragraph IV Notice Letter and believe they do not have merit, and we intend to prosecute vigorously our patent infringement claims against Par. In connection with an administrative review by NIH of the grants that were the subject of the Klein lawsuit, we reimbursed the NIH $1.1 million in October 2013. The payment was recorded as selling, general and administrative expense in the accompanying Consolidated Statement of Operations and Comprehensive Loss. In October 2013, we and our chief executive officer entered into a settlement agreement with our former insurer related to our former insurer’s defense of, and coverage obligations related to, the Klein lawsuit. Per the settlement agreement, we received $12.5 million in October 2013 which we recorded as litigation settlement in the accompanying Consolidated Statements of Operation and Comprehensive Loss. We considered this particular litigation settlement an infrequent item given the nature of the lawsuit and have included the settlement as a separate component of non-operating income.

Shareholders' Equity

Shareholders' Equity	12 Months Ended
	Dec. 31, 2015
Equity [Abstract]
Shareholders' Equity	Shareholders’ Equity Common Stock As of December 31, 2015 , we had reserved shares of common stock for the following purposes: Options granted and outstanding 8,310,235 Options available for future grant 1,724,987 Common stock warrants 749,250 Total shares reserved 10,784,472 Options Available for Future Grant - On January 1, 2016 , an additional 1,785,714 shares became available for future issuance under the 2008 Equity Incentive Plan (the 2008 Plan) in accordance with the annual increase provisions of the 2008 Plan. These additional shares are not included in the table above. At Market Issuance Sales Agreement - In January 2016, we entered into an At Market Issuance Sales Agreement (the ATM Agreement) with JonesTrading Institutional Services LLC (JonesTrading) pursuant to which we may direct JonesTrading to sell shares of our common stock with an aggregate offering price of up to $100 million directly on The Nasdaq Global Market, through a market maker other than on an exchange or in negotiated transactions. Any sales made under the ATM Agreement are based solely on our instructions and JonesTrading will receive a 1.7% commission from the gross proceeds. The ATM Agreement may be terminated by either party at any time upon 10 days ' notice to the other party or by JonesTrading at any time in certain circumstances including the occurrence of a material adverse effect to Omeros. Securities Offerings - In February 2015, we sold 3.4 million shares of our common stock at a public offering price of $20.03 and sold pre-funded warrants to purchase up to 749,250 shares of our common stock at a public offering price of $20.02 per pre-funded warrant share. The public offering price for the pre-funded warrants was equal to the public offering price of the common stock, less the $0.01 per share exercise price of each pre-funded warrant. After deducting underwriter discounts and offering expenses of $4.9 million , we received net proceeds from the transaction of $79.1 million . In March 2014, we sold 3.5 million shares of our common stock at a public offering price of $11.50 per share. After deducting underwriter discounts and offering expenses of $2.5 million , we received net proceeds from the transaction of $37.8 million . In October 2013, we sold 374,000 shares of our common stock with a weighted average price of $13.29 per share under an at-the-market sales agreement and received $4.9 million in net proceeds. The agreement expired in April 2014. In May 2013, we sold 3.9 million shares of our common stock at a price of $4.14 per share in a registered direct offering. After deducting offering expenses of $39,000 , we received net proceeds from the transaction of $16.1 million . Warrants The following table summarizes our outstanding pre-funded warrants at December 31, 2015 , which have an exercise price of $0.01 : Outstanding At Expiration Date Exercise Price 749,250 February 2, 2022 $0.01 In March 2009, we issued warrants with an exercise price of $12.25 per share to brokers who assisted us in our Series E financing (the Series E Warrants). In March 2013, we extended the expiration dates of the Series E Warrants by one year and in each of March 2014 and September 2014 we extended their expiration by six months. We evaluated the fair value of the Series E Warrants before and after each modification, and we recorded $863,000 and $41,000 change in fair value as other expense in the accompanying Consolidated Statement of Operations and Comprehensive Loss for the years ended December 31, 2014 and 2013, respectively. For the year ending December 31, 2014, Series E Warrants were exercised, through cash and cashless net exercise, resulting in cash proceeds of $68,000 and the issuance of 28,653 shares of our common stock. Additionally, for the year ended December 31, 2015, we received cash proceeds of $1.4 million upon the cash and cashless exercise of Series E Warrants which resulted in the issuance of 133,240 shares of our common stock.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	Stock-Based Compensation The 2008 Plan provides for the grant of incentive and non-statutory stock options, restricted stock, stock appreciation rights, performance units and performance shares to employees, directors and consultants and subsidiary corporations’ employees and consultants. Options are granted with exercise prices equal to the closing fair market value of the common stock on the date of the grant. The terms of options may not exceed 10 years and options generally vest over a four -year period. The 2008 Plan also allows any shares returned under our Amended and Restated 1998 Stock Option Plan (the 1998 Plan), as a result of cancellation of options or repurchase of shares issued pursuant to the 1998 Plan, to be issued under the 2008 Plan. In addition, the 2008 Plan provides for annual increases in the number of shares available for issuance thereunder on the first day of each year, equal to the lower of: • five percent of the outstanding shares of our common stock on the last day of the preceding year; • 1,785,714 shares; or • such other amount as our board of directors may determine. As of December 31, 2015 , a total of 10,035,222 shares were reserved for issuance under our stock plans, of which 1,724,987 were available for future grants. On January 1, 2016 , an additional 1,785,714 shares became available for future issuance under our 2008 Plan in accordance with the annual increase. In February 2016, approximately 1.3 million shares were granted to employees related to annual performance grants. Compensation cost for stock options granted to employees and directors is based on the grant-date fair value and is recognized over the vesting period of the applicable option on a straight-line basis. Stock-based compensation expense is based on options ultimately expected to vest, and therefore has been reduced for estimated forfeitures. We estimate forfeitures based on our historical experience; separate groups of employees that have similar historical forfeiture behavior are considered separately for expense recognition. The fair value of each option grant to employees and directors is estimated on the date of grant using the Black-Scholes option-pricing model. The following assumptions were applied to employee & director stock option grants during the periods ended: Year Ended December 31, 2015 2014 2013 Estimated weighted-average fair value $ 11.31 $ 7.39 $ 6.87 Weighted-average assumptions: Expected volatility 71 % 73 % 88 % Expected term, in years 6.0 5.8 5.8 Risk-free interest rate 1.68 % 1.87 % 1.66 % Expected dividend yield — % — % — % (A) Expected Volatility. Prior to October 14, 2014 the expected volatility rate used to value stock option grants was based on volatilities of a peer group of similar companies whose share prices were publicly available due to our limited trading history. The peer group was developed based on companies in the pharmaceutical and biotechnology industry in a similar stage of development. As of October 2014, we determined it was appropriate to rely 100% on our own historical realized volatility given our own trading history was roughly equivalent to the average expected term of our options and we do not anticipate future volatility will differ significantly from the past. This change in estimate did not have a material impact on our operating income, net income or earnings per share. (B) Expected Term. We elected to utilize the “simplified” method for “plain vanilla” options to determine the expected term of our stock option grants. We will continue to use the simplified method until we have sufficient historical data necessary to provide a reasonable estimate of expected life based on the exercise behavior of our option holders. Under this approach, the weighted-average expected life is presumed to be the average of the vesting term and the contractual term of the option. (C) Risk-free Interest Rate. The risk-free interest rate assumption was based on zero-coupon U.S. Treasury instruments that had terms consistent with the expected term of our stock option grants. (D) Expected Dividend Yield. We have never declared or paid any cash dividends and do not presently plan to pay cash dividends in the foreseeable future. Stock options granted to non-employees are accounted for using the fair-value approach. The fair value of non-employee option grants is estimated using the Black-Scholes option-pricing model and are re-measured over the vesting term as earned. The estimated fair value is charged to expense over the applicable service period. During the years ended December 31, 2015 , 2014 and 2013 , we granted to non-employees options to purchase 4,200 shares, 86,000 shares and 40,000 shares of common stock, respectively. Stock-based compensation expense includes amortization of stock options granted to employees and non-employees and has been reported in our Consolidated Statements of Operations and Comprehensive Loss as follows: Year Ended December 31, 2015 2014 2013 (In thousands) Research and development $ 4,977 $ 4,754 $ 3,588 Selling, general and administrative 4,604 4,164 2,664 Total stock-based compensation expense $ 9,581 $ 8,918 $ 6,252 In connection with the non-employee options, we recognized expense of $ 492,000 , $289,000 and $71,000 during the years ended December 31, 2015 , 2014 and 2013 , respectively. Stock option activity for all stock plans is as follows: Options Outstanding Weighted- Average Exercise Price per Share Remaining Contractual Life (in years) Aggregate Intrinsic Value (In thousands) Balance at December 31, 2014 8,364,469 $ 7.52 Granted 350,975 17.90 Exercised (277,356 ) 5.13 Forfeited and expired (127,853 ) 12.36 Balance at December 31, 2015 8,310,235 $ 7.97 6.07 $ 65,610 Vested and expected to vest at December 31, 2015 8,096,339 $ 7.85 6.00 $ 64,731 Exercisable at December 31, 2015 6,217,364 $ 6.61 5.24 $ 56,757 The total intrinsic value of options exercised during the years ended December 31, 2015 , 2014 and 2013 was $3.9 million , $2.9 million and $1.1 million , respectively. Information about stock options outstanding and exercisable is as follows: December 31, 2015 Options Outstanding Options Exercisable Range of Exercise Price Number of Options Weighted- Average Remaining Contractual Life (Years) Weighted- Average Exercise Price Number of Options Weighted- Average Exercise Price $0.98-$4.09 1,434,412 1.07 $ 1.17 1,434,412 $ 1.17 $4.10-$8.00 1,975,794 5.12 5.25 1,958,011 5.23 $8.01-$11.42 2,735,818 7.17 9.79 2,063,009 9.81 $11.43-$25.00 2,164,211 8.86 12.66 761,932 11.73 $0.98-$25.00 8,310,235 6.07 $ 7.97 6,217,364 $ 6.61 At December 31, 2015 , there were 2,092,871 unvested options outstanding that will vest over a weighted-average period of 2.1 years. Excluding non-employee stock options, the remaining estimated compensation expense to be recognized in connection with these options is $12.9 million .

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes We have a history of losses and therefore have made no provision for income taxes. Deferred income taxes reflect the tax effect of net operating loss and tax credit carryforwards and the net temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Significant components of deferred tax assets are as follows: December 31, 2015 2014 (In thousands) Deferred tax assets: Net operating loss carryforwards $ 110,092 $ 88,399 Tax credit carryforwards 14,758 9,569 Stock-based compensation 8,136 5,511 Deferred rent 3,324 3,077 Other 2,744 2,084 Total deferred tax assets 139,054 108,640 Less valuation allowance (139,054 ) (108,640 ) Net deferred tax assets $ — $ — As of December 31, 2015 and 2014 , we had Federal net operating loss carryforwards of approximately $325.9 million and $264.1 million , respectively, state net operating losses of approximately $30.6 million and $100,000 , respectively, and tax credit carryforwards of approximately $14.8 million and $9.6 million , respectively. Approximately $5.9 million of our net operating loss carryforwards relate to tax deductible stock-based compensation in excess of amounts recognized for financial statement purposes. To the extent that net operating loss carryforwards, if realized, relate to stock-based compensation, the resulting tax benefits will be recorded to shareholders’ equity, rather than to the results of operations. In certain circumstances, due to ownership changes, our net operating loss and tax credit carryforwards may be subject to limitations under Section 382 of the Internal Revenue Code. To date, we have not completed a Section 382 study. Unless previously utilized, our net operating loss and research and development tax credit carryforwards expire between 2018 and 2035 . We have established a 100% valuation allowance due to the uncertainty of our ability to generate sufficient taxable income to realize the deferred tax assets. Our valuation allowance increased $30.4 million , $25.8 million and $14.5 million in 2015 , 2014 and 2013 , respectively, primarily due to net operating losses incurred during these periods. Reconciliation of income tax computed at Federal statutory rates to the reported provisions for income taxes is as follows: Year ended December 31, 2015 2014 2013 Federal statutory tax rate (34 )% (34 )% (34 )% State tax rates (2 )% — % — % Other permanent differences 1 % 2 % 3 % Change in valuation allowance 41 % 35 % 36 % Tax credits (5 )% (4 )% (5 )% Other (1 )% 1 % — % Effective tax rate — % — % — % We file Federal and state income tax returns, which provides varying statutes of limitations on assessments. However, because of net operating loss carryforwards, substantially all of our tax years remain open to federal and state tax examination. The guidance for accounting for uncertainties in income taxes requires that we recognize the financial statement effects of a tax position when it is more likely than not, based on the technical merits, that the position will be sustained upon examination. As of December 31, 2015 , 2014 and 2013 , we maintained an uncertain tax position of $212,000 related to a reduction of our research and development credit deferred tax asset. Further, there were no unrecognized tax benefits that, if recognized, would impact our effective tax rate. We recognize interest and penalties related to the underpayment of income taxes as a component of income tax expense. To date, there have been no interest or penalties charged to us in relation to the underpayment of income taxes.

401 Retirement Plan

401 Retirement Plan	12 Months Ended
	Dec. 31, 2015
Text Block [Abstract]
401(k) Retirement Plan	401(k) Retirement Plan We have adopted a 401(k) plan. To date, we have not matched employee contributions to the plan. All employees are eligible to participate, provided they meet the requirements of the plan.

Quarterly Information (Unaudite

Quarterly Information (Unaudited)	12 Months Ended
	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Quarterly Information (Unaudited)	Quarterly Information (Unaudited) The following table summarizes the unaudited statements of operations and comprehensive loss for each quarter of 2015 and 2014 (in thousands, except per share amounts): 2015 For the Quarter Ended March 31, June 30, September 30, December 31, Revenue $ 388 $ 3,187 $ 3,259 $ 6,675 Total operating expenses 18,318 19,154 22,560 24,715 Loss from operations (17,930 ) (15,967 ) (19,301 ) (18,040 ) Net loss (18,669 ) (16,680 ) (19,921 ) (19,826 ) Basic and diluted net loss per share $ (0.51 ) $ (0.44 ) $ (0.53 ) $ (0.52 ) 2014 For the Quarter Ended March 31, June 30, September 30, December 31, Revenue $ 100 $ 45 $ 214 $ 180 Total operating expenses 15,784 17,262 17,346 20,155 Loss from operations (15,684 ) (17,217 ) (17,132 ) (19,975 ) Net loss (16,642 ) (17,991 ) (18,327 ) (20,713 ) Basic and diluted net loss per share $ (0.54 ) $ (0.53 ) $ (0.54 ) $ (0.61 )

Significant Accounting Polici21

Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Organization	Organization We are a biopharmaceutical company committed to discovering, developing and commercializing both small-molecule and protein therapeutics for large-market as well as orphan indications targeting inflammation, coagulopathies and disorders of the central nervous system.
Basis of Presentation	Basis of Presentation Our consolidated financial statements include the financial position and results of operations of Omeros Corporation (Omeros) and our wholly owned subsidiaries. All inter-company transactions have been eliminated. The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (GAAP). We generated net losses of $75.1 million , $73.7 million and $39.8 million in 2015 , 2014 and 2013 , respectively, and as of December 31, 2015 , we had $28.3 million in cash, cash equivalents and short-term investments available for general corporate use. In addition, in restricted cash and investments we have $10 million that must be maintained in depository and investment accounts pursuant to the new Loan and Security Agreement (the Oxford/EWB Loan Agreement) with Oxford and EastWest Bank (EWB) as well as $679,000 used to secure a letter of credit for the Omeros Building lease. We expect to continue to incur losses until such time as OMIDRIA product sales, corporate partnerships and/or licensing revenues from products or programs are adequate to support our ongoing operating expenses and debt service. We are unable to predict if or when this may occur, and until it does occur, we will need to continue to raise additional funds through public or private equity securities sales including our ATM with JonesTrading (see Note 10 for further detail), through the issuance of additional debt, through corporate partnerships, through asset sales or through the pursuit of collaborations and licensing arrangements related to certain of our products or programs. These conditions raise a substantial doubt about our ability to continue as a going concern. If we are unable to become cash-flow positive or to raise additional capital as and when needed, or upon acceptable terms, such failure would have a significant negative impact on our financial condition. The accompanying consolidated financial statements have been prepared on a going-concern basis, which contemplates the realization of assets and the satisfaction of liabilities in the normal course of business. The accompanying consolidated financial statements do not include any adjustments to reflect the possible future effects on the recoverability and classification of assets or the amounts and classification of liabilities that may result from uncertainty related to our ability to continue as a going concern.
Segments	Segments We operate in one segment. Management uses cash flow as the primary measure to manage our business and does not segment our business for internal reporting or decision-making.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Significant items subject to such estimates include revenue recognition, stock-based compensation expense and accruals for clinical trials and contingencies. We base our estimates on historical experience and on various other factors that we believe are reasonable under the circumstances; however, actual results could differ from these estimates.
Reclassification	Reclassifications Certain reclassifications have been made to prior periods in the consolidated financial statements and the accompanying notes to conform with the current presentation, none of which impacted our net loss or working capital.
Cash and Cash Equivalents Disclosure	Cash and Cash Equivalents, Short-Term Investments, and Restricted Cash and Investments Cash and cash equivalents include highly liquid investments with a maturity of three months or less on the date of purchase. Short-term investment securities are classified as available-for-sale and are carried at fair value. Unrealized gains and losses, if any, are reported as a separate component of shareholders’ deficit. Amortization, accretion, interest and dividends, realized gains and losses and declines in value judged to be other-than-temporary are included in other income (expense). The cost of securities sold is based on the specific-identification method. Investments in securities with maturities of less than one year, or those for which management intends to use the investments to fund current operations, are included in current assets. We evaluate whether an investment is other-than-temporarily impaired based on the specific facts and circumstances. Factors that are considered in determining whether an other-than-temporary decline in value has occurred include: the market value of the security in relation to its cost basis; the financial condition of the investee; and the intent and ability to retain the investment for a sufficient period of time to allow for recovery in the market value of the investment. Restricted cash and investments are held in certificates of deposit and money-market funds.
Inventory	Inventory Inventory is stated at the lower of cost or market determined on a specific identification basis in a manner which approximates the first-in, first-out (FIFO) method. Costs include amounts related to third party manufacturing, transportation and internal labor and overhead. Capitalization of costs as inventory begins when the product candidate receives regulatory approval in the U.S. or the European Union (EU), which for OMIDRIA began upon U.S. regulatory approval in May 2014. We expense inventory costs related to product candidates as research and development expenses prior to receiving regulatory approval in the respective territory. Inventory is reduced to net realizable value for excess and obsolete inventories based on forecasted demand.
Grant and Other Receivables	Receivables Receivables relate primarily to sales of OMIDRIA to wholesalers and include reductions for estimated chargebacks, rebates, and product returns which are expected to be settled through reductions in receivables. Remaining receivables consist of amounts related to grants from the National Institutes of Health (NIH) and subleases for space in The Omeros Building. Considering the nature and historic collectability of our receivables, we concluded an allowance for doubtful accounts is not necessary as of December 31, 2015 and 2014 .
Property and Equipment	Property and Equipment, net Property and equipment are stated at cost and depreciation is calculated using the straight-line method over the estimated useful life of the assets, which is generally three to ten years. Equipment financed under capital leases is recorded as property and equipment and is amortized over the shorter of the useful lives of the related assets or the lease term. Expenditures for equipment purchased with grant funds are recorded as a reduction to the cost of the applicable equipment. Expenditures for repairs and maintenance are expensed as incurred.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets The carrying amount of long-lived assets is reviewed whenever events or changes in circumstances indicate that the carrying value of an asset may not be recoverable. Recoverability of these assets is measured by comparing the carrying value to future undiscounted cash flows the asset is expected to generate. If the asset is considered to be impaired, the amount of any impairment will be reflected in the results of operations in the period of impairment. We have not recognized any impairment losses for the years ending December 31, 2015 , 2014 and 2013 .
Deferred Rent	Deferred Rent We recognize rent expense on a straight-line basis over the noncancelable term of The Omeros Building operating lease and, accordingly, record the difference between cash rent payments and the recognition of rent expense as an increase or decrease in deferred rent liability. We also record landlord-funded lease incentives, such as reimbursable leasehold improvements, as an increase in deferred rent liability which is amortized as a reduction of rent expense over the noncancelable terms of The Omeros Building operating lease.
Revenue Recognition	Revenue Recognition Our revenues are comprised of product sales of OMIDRIA and amounts earned for services under grants from third parties. Revenue is recognized when there is persuasive evidence that an arrangement exists, product title and risk of loss is passed to the customer or the service has been provided, the price is fixed or determinable and collection is reasonably assured. Product Sales, Net We record revenue from product sales when the product is delivered to our wholesalers. Product sales to a wholesaler are not recorded if we determine that the wholesaler’s on-hand OMIDRIA inventory, based on inventory information we regularly receive from our wholesalers, exceeds approximately eight weeks of projected demand. Product sales are recorded net of chargebacks and rebates, wholesaler distribution fees and estimated product returns. Accruals or allowances are established for these deductions when revenue is recognized, and actual amounts incurred are offset against the applicable accruals or allowances. We reflect each of these accruals or allowances as either a reduction in the related account receivable or as an accrued liability, depending on how the amount is settled. Provisions for chargebacks are determined utilizing historical and projected payer mix and sale-through and inventory on-hand information received directly from wholesalers. Chargebacks are generally settled within four weeks of recording product sales revenue. We provide reimbursement support services and financial assistance in the form of a rebate to patients whose commercial insurance is inadequate to cover the full cost of OMIDRIA. We apply an experience ratio to product sales to determine the rebate accrual. This experience ratio is reviewed and updated periodically to reflect actual results. We allow for the return of product up to 12 months past its expiration date or for product that is damaged. In estimating product returns, we take into consideration our single-tier distribution model, our expectation that product is typically not held by the healthcare providers based on the frequency of their reorders, inventory in the wholesale channel, our return experience to date, the remaining shelf life of product we have previously sold and historical industry return rates. We pay our wholesalers a distribution fee for services they perform on our behalf based on a contractual rate.
Research and Development	Research and Development Research and development costs are comprised primarily of costs for personnel, including salaries, benefits and stock compensation; an allocation of our occupancy costs; clinical study costs; contracted research; manufacturing; consulting arrangements; depreciation; materials and supplies; milestones; and other expenses incurred to sustain our overall research and development programs. Research and development costs are expensed as incurred. Advance payments for goods or services that will be used or rendered for future research and development activities are deferred and then recognized as an expense as the related goods are delivered or the services are performed, or when the goods or services are no longer expected to be provided.
Patents	Patents We generally apply for patent protection on processes and product candidates we or our licensors conceive or develop. Patent costs are comprised primarily of external legal fees, filing fees incurred to file patent applications, and periodic renewal fees to keep the patent in force and are expensed as incurred as a component of general and administrative expense.
Selling, General and Administrative Expenses, Policy	Selling, General and Administrative Selling, general and administrative (SG&A) expenses are comprised primarily of salaries, service fees incurred for our dedicated contracted sales force, benefits, and stock-compensation costs for sales, marketing, and other personnel not directly engaged in research and development. Additionally, SG&A includes marketing and selling expenses, professional and legal services; patent costs; depreciation, an allocation of our occupancy costs; and other general corporate expenses. Effective January 1, 2016, we converted our dedicated contracted sales force provided by a third party to Omeros employees.
Advertising Cost, Policy, Expensed Advertising Cost	Advertising Advertising costs, which we consider to be media and marketing materials, are expensed as incurred. We incurred $ 885,000 in advertising expense during the year ended December 31, 2015 . We had no similar expenses during the years ended December 31, 2014 and 2013 , respectively.
Income Tax	Income Taxes Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their tax bases. Deferred tax assets and liabilities are measured using enacted tax rates applied to taxable income in the years in which those temporary differences are expected to be recovered or settled. We recognize the effect of income tax positions only if those positions are more likely than not of being sustained upon an examination. A valuation allowance is established when it is more likely than not that the deferred tax assets will not be realized.
Share-based Compensation	Stock-Based Compensation Stock-based compensation expense is recognized for all share-based payments made to employees, directors and non-employees based on estimated fair values. The fair value of our stock options is calculated using the Black-Scholes option-pricing model which requires judgmental assumptions including volatility, forfeiture rates and expected option life. We use the straight-line method to allocate compensation cost to reporting periods over each optionee’s requisite service period for employees and directors, which is generally the vesting period. Stock options granted to non-employees are accounted for using the fair-value approach and are subject to periodic revaluation over their vesting terms as earned.
Accumulated Other Comprehensive Loss	Accumulated Other Comprehensive Loss Accumulated other comprehensive loss is comprised of net loss and certain changes in equity that are excluded from net loss. There was no difference between comprehensive loss and net loss for the years ended December 31, 2015 , 2014 or 2013 .
Financial Instruments And Concentration Of Credit Risk	Financial Instruments and Concentrations of Credit Risk Cash and cash equivalents, receivables, accounts payable and accrued liabilities, which are recorded at invoiced amount or cost, approximate fair value based on the short-term nature of these financial instruments. The fair value of short-term investments is based on quoted market prices. Financial instruments that potentially subject us to concentrations of credit risk consist primarily of cash and cash equivalents, short-term investments and receivables. Cash and cash equivalents are held by financial institutions and are federally insured up to certain limits. At times, our cash and cash equivalents balance exceeds the federally insured limits. To limit the credit risk, we invest our excess cash in high quality securities such as money market mutual funds, certificates of deposit and commercial paper.
Major Customers, Policy	Major Customers We sell OMIDRIA through a limited number of wholesalers. Each of these wholesalers, together with entities under their common control, accounted for greater than 10% of total revenues for the year ended December 31, 2015 and greater than 10% of accounts receivable as of December 31, 2015 as noted below.
Concentration Risk Disclosure	Major Suppliers We use a small number of contract manufacturers to supply OMIDRIA and to produce clinical trial material which creates a concentration of risk for us. With regards to OMIDRIA, Patheon Manufacturing Services, LLC (Patheon) is completing the analytical testing required before transferring OMIDRIA commercial product, costing $1.3 million , to us. We anticipate receiving the product during the first quarter of 2016 and the product dating will allow the product to be sold through at least the third quarter of 2018. This is the final commercial supply of OMIDRIA that Patheon will be available to produce using Patheon’s facility currently approved for manufacturing OMIDRIA. We have entered into a non-exclusive agreement with Hospira Worldwide, Inc. (Hospira) for the ongoing commercial supply of OMIDRIA and we are currently completing the manufacturing process transfer, process validation and approval of Hospira as a manufacturing site for OMIDRIA. We anticipate Hospira will be able to provide OMIDRIA commercial product to us beginning in 2017. We believe the commercial supply of OMIDRIA currently undergoing final analytical testing at Patheon plus our OMIDRIA inventory on hand will be adequate to supply our needs of OMIDRIA until Hospira is able to supply our OMIDRIA commercial product needs. While one source of supply is utilized for OMIDRIA and generally one source for each of our product candidates, other sources are available should we need to change suppliers. We endeavor to maintain reasonable levels of drug supply for our commercial and clinical trial use. A change in suppliers, however, could cause a delay in delivery of OMIDRIA or our clinical trial material that would adversely affect our business.
Significant Accounting Policies	Recently Adopted Accounting Pronouncements For the year ended December 31, 2015 we adopted and applied retrospectively Financial Accounting Standards Board (FASB) Accounting Standards Update, or ASU, No. 2015-03, related to simplifying the presentation of debt issuance costs. This standard requires debt issuance costs related to a recognized debt liability to be presented in the balance sheet as a direct deduction to the liability. The adoption of ASU 2015-03 resulted in the reclassification of $300,000 of debt issuance costs from Other Current Assets and Other Assets to Current Portion of Notes Payable and Notes Payable in our December 31, 2014 Consolidated Balance Sheet. In November 2015, FASB issued ASU, No. 2015-17 that simplifies the presentation of deferred tax assets and liabilities by jurisdiction, along with any related valuation allowance. The new guidance requires companies to classify all deferred tax assets and liabilities as noncurrent on the balance sheet. We have elected to apply this standard prospectively for the year ended December 31, 2015. As we have a full valuation allowance against our deferred tax assets for all periods presented, the adoption had no material impact on the presentation of our financial condition, results of operations, cash flow and financial statement disclosures. Recent Accounting Pronouncements In February 2016, FASB issued ASU 2016-02 related to lease accounting. This standard requires lessees to recognize a right-of-use asset and a lease liability for most leases. This standard must be applied using a modified retrospective transition and is effective for all annual and interim periods beginning after December 15, 2018. Earlier adoption is permitted. We are evaluating how this new standard will impact the presentation of our financial statements and related disclosures. In July 2015, FASB issued ASU 2015-11 related to simplifying the measurement of inventory. This standard requires inventory to be measured at the lower of cost or net realizable value. This standard must be applied prospectively and is effective for all annual and interim periods beginning after December 15, 2016. Earlier application is permitted as of the beginning of an interim or annual reporting period. This standard is not expected to have a material impact on the presentation of the our financial position. In August 2014, FASB issued ASU No. 2014-15 related to disclosure of an entity’s ability to continue as a going concern. This standard requires management to evaluate whether substantial doubt exists regarding the entity’s ability to continue as a going concern at each reporting period for a duration of one year after the date the financial statements are issued or available to be issued. The standard establishes certain required disclosures if substantial doubt exists. This standard must be applied prospectively and is effective for interim and annual periods beginning after December 15, 2016. We will review the impact of the standard upon our disclosures, if applicable, beginning in 2017. In May 2014, FASB issued ASU No. 2014-09 related to the recognition of revenue that supersedes existing guidance. This standard clarifies the principles for recognizing revenue utilizing a five-step process. This standard must be applied retroactively to each prior reporting period presented, or retrospectively with the cumulative effect of applying the standard recognized in the period adopted. As amended, the standard is effective for interim and annual periods beginning after December 15, 2017 and cannot be adopted before that effective date. We are currently evaluating the impact that this standard may have on our financial statements once it is adopted.

Significant Accounting Polici22

Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Schedule of Revenue by Major Customers by Reporting Segments	We sell OMIDRIA through a limited number of wholesalers. Each of these wholesalers, together with entities under their common control, accounted for greater than 10% of total revenues for the year ended December 31, 2015 and greater than 10% of accounts receivable as of December 31, 2015 as noted below. Percentage of Total Revenue Percentage of Accounts Receivable Distributor A 37% 45% Distributor B 31% 23% Distributor C 28% 27%

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	12 Months Ended
	Dec. 31, 2015
Earnings Per Share [Abstract]
Calculation of Historical Outstanding Dilutive Securities Not Included in Diluted Loss per Share	Potentially dilutive securities excluded from the diluted loss per share calculation are as follows: Year Ended December 31, 2015 2014 2013 Outstanding options to purchase common stock 8,310,235 8,364,469 6,969,303 Warrants and pre-funded warrants to purchase common stock 749,250 551,435 609,016 Total potentially dilutive securities 9,059,485 8,915,904 7,578,319

Fair-Value Measurements (Tables

Fair-Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2015
Fair Value Disclosures [Abstract]
Financial Assets and Liabilities Measured at Fair Value on Recurring Basis	Our fair-value hierarchy for our financial assets and liabilities measured at fair value on a recurring basis are as follows: December 31, 2015 Level 1 Level 2 Level 3 Total (In thousands) Assets: Money-market funds classified as non-current restricted cash and investments $ 10,679 $ — $ — $ 10,679 Money-market funds classified as short-term investments 26,898 — — 26,898 Total $ 37,577 $ — $ — $ 37,577 December 31, 2014 Level 1 Level 2 Level 3 Total (In thousands) Assets: Money-market funds classified as non-current restricted cash and investments $ 679 $ — $ — $ 679 Money-market funds classified as short-term investments 6,532 — — 6,532 Total $ 7,211 $ — $ — $ 7,211

Certain Balance Sheet Accounts

Certain Balance Sheet Accounts (Tables)	12 Months Ended
	Dec. 31, 2015
Balance Sheet Related Disclosures [Abstract]
Grant and Other Receivables	December 31, 2015 2014 (In thousands) Trade receivables, net $ 6,208 $ — Grant receivables 136 324 Other receivables 173 68 Total receivables $ 6,517 $ 392
Inventory Disclosure [Text Block]	Inventory December 31, 2015 2014 (In thousands) Raw materials $ 93 $ — Work-in-process 158 — Finished goods 221 568 Total inventory $ 472 $ 568
Property and Equipment	December 31, 2015 2014 (In thousands) Laboratory equipment $ 1,735 $ 1,636 Office equipment and furniture 625 615 Computer equipment 482 403 Capital lease equipment 367 230 Computer software 174 126 Total cost 3,383 3,010 Less accumulated depreciation and amortization (2,432 ) (2,228 ) Total property and equipment, net $ 951 $ 782 For the years ended December 31, 2015 , 2014 and 2013 , depreciation and amortization expense was $209,000 , $317,000 and $302,000 , respectively.
Accrued Expenses	December 31, 2015 2014 (In thousands) Contract research and development $ 2,973 $ 1,280 Employee compensation 2,590 2,421 Consulting and professional fees 2,400 1,952 Clinical trials 1,108 828 Other accruals 681 589 Total accrued liabilities $ 9,752 $ 7,070

Notes Payable (Tables)

Notes Payable (Tables)	12 Months Ended
	Dec. 31, 2015
Debt Disclosure [Abstract]
Contractual Obligation, Fiscal Year Maturity Schedule	Future principal payments as of December 31, 2015 under the Oxford/EWB Loan Agreement and our capital equipment financing leases, based on stated contractual maturities, are as follows: Year Ending December 31, Total (In thousands) 2016 $ 73 2017 7,627 2018 19,432 2019 21,258 2020 1,891 Total future principal payments $ 50,281 The principal payments reflected in the table above exclude the $436,000 unamortized balance of the debt discount.

Revenue (Tables)

Revenue (Tables)	12 Months Ended
	Dec. 31, 2015
Revenue Recognition [Abstract]
Revenue, by Arrangement, Disclosure	Revenues recognized from grants are as follows: Year Ended December 31, 2015 2014 2013 (In thousands) Small Business Innovative Research Grants (SBIR) $ 245 $ 539 $ 630 Vulcan Inc. — — 970 Total revenue $ 245 $ 539 $ 1,600

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Future Minimum Payments Related Operating Lease	Future minimum payments related to these leases and The Omeros Building lease, which exclude common area maintenance and related operating expenses, at December 31, 2015 , are as follows: Year Ending December 31, Lease Sublease Net Lease (In thousands) 2016 $ 4,106 $ 682 $ 3,424 2017 4,188 580 3,608 2018 4,259 — 4,259 2019 4,350 — 4,350 2020 4,450 — 4,450 Thereafter 33,263 — 33,263 Total $ 54,616 $ 1,262 $ 53,354

Shareholders' Equity (Tables)

Shareholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2015
Equity [Abstract]
Reserved Shares of Common Stock	As of December 31, 2015 , we had reserved shares of common stock for the following purposes: Options granted and outstanding 8,310,235 Options available for future grant 1,724,987 Common stock warrants 749,250 Total shares reserved 10,784,472
Schedule of Stockholders' Equity Note, Warrants or Rights	The following table summarizes our outstanding pre-funded warrants at December 31, 2015 , which have an exercise price of $0.01 : Outstanding At Expiration Date Exercise Price 749,250 February 2, 2022 $0.01

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Weighted Average Assumptions For Employee Stock Option Grants	Compensation cost for stock options granted to employees and directors is based on the grant-date fair value and is recognized over the vesting period of the applicable option on a straight-line basis. Stock-based compensation expense is based on options ultimately expected to vest, and therefore has been reduced for estimated forfeitures. We estimate forfeitures based on our historical experience; separate groups of employees that have similar historical forfeiture behavior are considered separately for expense recognition. The fair value of each option grant to employees and directors is estimated on the date of grant using the Black-Scholes option-pricing model. The following assumptions were applied to employee & director stock option grants during the periods ended: Year Ended December 31, 2015 2014 2013 Estimated weighted-average fair value $ 11.31 $ 7.39 $ 6.87 Weighted-average assumptions: Expected volatility 71 % 73 % 88 % Expected term, in years 6.0 5.8 5.8 Risk-free interest rate 1.68 % 1.87 % 1.66 % Expected dividend yield — % — % — % (A) Expected Volatility. Prior to October 14, 2014 the expected volatility rate used to value stock option grants was based on volatilities of a peer group of similar companies whose share prices were publicly available due to our limited trading history. The peer group was developed based on companies in the pharmaceutical and biotechnology industry in a similar stage of development. As of October 2014, we determined it was appropriate to rely 100% on our own historical realized volatility given our own trading history was roughly equivalent to the average expected term of our options and we do not anticipate future volatility will differ significantly from the past. This change in estimate did not have a material impact on our operating income, net income or earnings per share. (B) Expected Term. We elected to utilize the “simplified” method for “plain vanilla” options to determine the expected term of our stock option grants. We will continue to use the simplified method until we have sufficient historical data necessary to provide a reasonable estimate of expected life based on the exercise behavior of our option holders. Under this approach, the weighted-average expected life is presumed to be the average of the vesting term and the contractual term of the option. (C) Risk-free Interest Rate. The risk-free interest rate assumption was based on zero-coupon U.S. Treasury instruments that had terms consistent with the expected term of our stock option grants. (D) Expected Dividend Yield. We have never declared or paid any cash dividends and do not presently plan to pay cash dividends in the foreseeable future.
Stock-Based Compensation Expense	Stock-based compensation expense includes amortization of stock options granted to employees and non-employees and has been reported in our Consolidated Statements of Operations and Comprehensive Loss as follows: Year Ended December 31, 2015 2014 2013 (In thousands) Research and development $ 4,977 $ 4,754 $ 3,588 Selling, general and administrative 4,604 4,164 2,664 Total stock-based compensation expense $ 9,581 $ 8,918 $ 6,252 In connection with the non-employee options, we recognized expense of $ 492,000 , $289,000 and $71,000 during the years ended December 31, 2015 , 2014 and 2013 , respectively.
Stock Option Activity and Related Information	Stock option activity for all stock plans is as follows: Options Outstanding Weighted- Average Exercise Price per Share Remaining Contractual Life (in years) Aggregate Intrinsic Value (In thousands) Balance at December 31, 2014 8,364,469 $ 7.52 Granted 350,975 17.90 Exercised (277,356 ) 5.13 Forfeited and expired (127,853 ) 12.36 Balance at December 31, 2015 8,310,235 $ 7.97 6.07 $ 65,610 Vested and expected to vest at December 31, 2015 8,096,339 $ 7.85 6.00 $ 64,731 Exercisable at December 31, 2015 6,217,364 $ 6.61 5.24 $ 56,757
Stock Options Outstanding and Exercisable	Information about stock options outstanding and exercisable is as follows: December 31, 2015 Options Outstanding Options Exercisable Range of Exercise Price Number of Options Weighted- Average Remaining Contractual Life (Years) Weighted- Average Exercise Price Number of Options Weighted- Average Exercise Price $0.98-$4.09 1,434,412 1.07 $ 1.17 1,434,412 $ 1.17 $4.10-$8.00 1,975,794 5.12 5.25 1,958,011 5.23 $8.01-$11.42 2,735,818 7.17 9.79 2,063,009 9.81 $11.43-$25.00 2,164,211 8.86 12.66 761,932 11.73 $0.98-$25.00 8,310,235 6.07 $ 7.97 6,217,364 $ 6.61

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Significant Components of Deferred Tax Assets	Significant components of deferred tax assets are as follows: December 31, 2015 2014 (In thousands) Deferred tax assets: Net operating loss carryforwards $ 110,092 $ 88,399 Tax credit carryforwards 14,758 9,569 Stock-based compensation 8,136 5,511 Deferred rent 3,324 3,077 Other 2,744 2,084 Total deferred tax assets 139,054 108,640 Less valuation allowance (139,054 ) (108,640 ) Net deferred tax assets $ — $ —
Reconciliation of Federal Statutory Tax Rate to Effective Income Tax	econciliation of income tax computed at Federal statutory rates to the reported provisions for income taxes is as follows: Year ended December 31, 2015 2014 2013 Federal statutory tax rate (34 )% (34 )% (34 )% State tax rates (2 )% — % — % Other permanent differences 1 % 2 % 3 % Change in valuation allowance 41 % 35 % 36 % Tax credits (5 )% (4 )% (5 )% Other (1 )% 1 % — % Effective tax rate — % — % — %

Quarterly Information (Unaudi32

Quarterly Information (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Summary of Unaudited Statements of Operations	The following table summarizes the unaudited statements of operations and comprehensive loss for each quarter of 2015 and 2014 (in thousands, except per share amounts): 2015 For the Quarter Ended March 31, June 30, September 30, December 31, Revenue $ 388 $ 3,187 $ 3,259 $ 6,675 Total operating expenses 18,318 19,154 22,560 24,715 Loss from operations (17,930 ) (15,967 ) (19,301 ) (18,040 ) Net loss (18,669 ) (16,680 ) (19,921 ) (19,826 ) Basic and diluted net loss per share $ (0.51 ) $ (0.44 ) $ (0.53 ) $ (0.52 ) 2014 For the Quarter Ended March 31, June 30, September 30, December 31, Revenue $ 100 $ 45 $ 214 $ 180 Total operating expenses 15,784 17,262 17,346 20,155 Loss from operations (15,684 ) (17,217 ) (17,132 ) (19,975 ) Net loss (16,642 ) (17,991 ) (18,327 ) (20,713 ) Basic and diluted net loss per share $ (0.54 ) $ (0.53 ) $ (0.54 ) $ (0.61 )

Organization and Basis of Pre33

Organization and Basis of Presentation - Additional Information (Detail) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015USD ($)	Sep. 30, 2015USD ($)	Jun. 30, 2015USD ($)	Mar. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Sep. 30, 2014USD ($)	Jun. 30, 2014USD ($)	Mar. 31, 2014USD ($)	Dec. 31, 2015USD ($)segment	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)
Accounting Policies [Abstract]
Number of operating segments | segment									1
Net loss	$ (19,826)	$ (19,921)	$ (16,680)	$ (18,669)	$ (20,713)	$ (18,327)	$ (17,991)	$ (16,642)	$ (75,096)	$ (73,673)	$ (39,796)
Cash, cash equivalents and marketable securities	28,300								28,300
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted Cash and Investments, Noncurrent	10,679								10,679
Cash and Eligible Investments
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted Cash and Investments, Noncurrent	10,000								10,000
Cash
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted Cash and Investments, Noncurrent	$ 679								$ 679

Significant Accounting Polici34

Significant Accounting Policies (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2015USD ($)
Property, Plant and Equipment [Line Items]
Advertising expense	$ 885
Minimum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	3 years
Maximum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life	10 years

Significant Accounting Polici35

Significant Accounting Policies Major Customers and Major Suppliers (Details) $ in Millions	12 Months Ended
	Dec. 31, 2015USD ($)supplier
Concentration Risk [Line Items]
Unrecorded purchase obligation | $	$ 1.3
Number of suppliers | supplier	1
Customer Concentration Risk | Distributor A | Percentage of Total Revenue
Concentration Risk [Line Items]
Concentration risk, percentage	37.00%
Customer Concentration Risk | Distributor A | Percentage of Accounts Receivable
Concentration Risk [Line Items]
Concentration risk, percentage	45.00%
Customer Concentration Risk | Distributor B | Percentage of Total Revenue
Concentration Risk [Line Items]
Concentration risk, percentage	31.00%
Customer Concentration Risk | Distributor B | Percentage of Accounts Receivable
Concentration Risk [Line Items]
Concentration risk, percentage	23.00%
Customer Concentration Risk | Distributor C | Percentage of Total Revenue
Concentration Risk [Line Items]
Concentration risk, percentage	28.00%
Customer Concentration Risk | Distributor C | Percentage of Accounts Receivable
Concentration Risk [Line Items]
Concentration risk, percentage	27.00%

Significant Accounting Polici36

Significant Accounting Policies Recently Adopted Accounting Pronouncements (Details) - New Accounting Pronouncement, Early Adoption, Effect $ in Thousands	Dec. 31, 2014USD ($)
Other Assets
New Accounting Pronouncement, Early Adoption [Line Items]
Debt issuance costs reclassified	$ 300
Debt
New Accounting Pronouncement, Early Adoption [Line Items]
Debt issuance costs reclassified	$ (300)

Net Loss Per Share - Calculatio

Net Loss Per Share - Calculation of Historical Outstanding Dilutive Securities Not Included in Diluted Loss Per Share (Detail) - shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Outstanding dilutive securities not included in diluted loss per share calculation	9,059,485	8,915,904	7,578,319
Outstanding options to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Outstanding dilutive securities not included in diluted loss per share calculation	8,310,235	8,364,469	6,969,303
Warrants and pre-funded warrants to purchase common stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Outstanding dilutive securities not included in diluted loss per share calculation	749,250	551,435	609,016

Fair-Value Measurements - Finan

Fair-Value Measurements - Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total	$ 37,577	$ 7,211
Money Market Funds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Money-market funds classified as short-term investments	26,898	6,532
Non Current
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Money-market funds classified as restricted cash	10,679	679
Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total	37,577	7,211
Fair Value, Inputs, Level 1 | Money Market Funds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Money-market funds classified as short-term investments	26,898	6,532
Fair Value, Inputs, Level 1 | Non Current
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Money-market funds classified as restricted cash	10,679	679
Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total	0	0
Fair Value, Inputs, Level 2 | Money Market Funds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Money-market funds classified as short-term investments	0	0
Fair Value, Inputs, Level 2 | Non Current
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Money-market funds classified as restricted cash	0	0
Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total	0	0
Fair Value, Inputs, Level 3 | Money Market Funds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Money-market funds classified as short-term investments	0	0
Fair Value, Inputs, Level 3 | Non Current
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Money-market funds classified as restricted cash	$ 0	$ 0

Fair-Value Measurements - Narra

Fair-Value Measurements - Narrative (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Cash excluded from fair value hierarchy disclosure	$ 1,400,000	$ 354,000
Unrealized gain (loss) on investments	$ 0	$ 0

Certain Balance Sheet Account40

Certain Balance Sheet Accounts - Grant and Other Receivables (Detail) - USD ($)	Dec. 31, 2015	Dec. 31, 2014
Balance Sheet Related Disclosures [Abstract]
Trade receivables, net	$ 6,208,000	$ 0
Grants receivable	136,000	324,000
Other receivables	173,000	68,000
Total receivables	6,517,000	$ 392,000
Deferred Discounts, Finance Charges and Interest Included in Receivables	$ 191,000

Certain Balance Sheet Account41

Certain Balance Sheet Accounts - Inventory (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Balance Sheet Related Disclosures [Abstract]
Raw materials	$ 93	$ 0
Work-in-process	158	0
Finished goods	221	568
Total inventory	$ 472	$ 568

Certain Balance Sheet Account42

Certain Balance Sheet Accounts - Property and Equipment (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 3,383	$ 3,010
Less accumulated depreciation and amortization	(2,432)	(2,228)
Total property and equipment, net	951	782
Depreciation and amortization	209	317	$ 302
Laboratory equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	1,735	1,636
Office equipment and furniture
Property, Plant and Equipment [Line Items]
Property and equipment, gross	625	615
Computer equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	482	403
Capital lease equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	367	230
Computer software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 174	$ 126

Certain Balance Sheet Account43

Certain Balance Sheet Accounts - Accrued Expenses (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Payables and Accruals [Abstract]
Contract research and development	$ 2,973	$ 1,280
Employee compensation	2,590	2,421
Consulting and professional fees	2,400	1,952
Clinical trials	1,108	828
Other accruals	681	589
Total accrued liabilities	$ 9,752	$ 7,070

Notes Payable - Additional Info

Notes Payable - Additional Information (Detail)	Mar. 11, 2014USD ($)	Dec. 31, 2015USD ($)tranche	Mar. 31, 2014USD ($)	Dec. 31, 2015USD ($)tranche	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)	Mar. 04, 2014USD ($)	Dec. 31, 2012USD ($)
Debt Instrument [Line Items]
Payments of debt extinguishment costs		$ 248,000
Loss on early extinguishment of debt				$ (1,315,000)	$ 0	$ 0
Unamortized balance of debt discount		436,000		436,000
Capital Leased Assets, Gross		367,000		367,000	230,000
Capital lease, accumulated depreciation		98,000		98,000	52,000
Capital lease, future minimum payments due		$ 281,000		$ 281,000	$ 185,000
Oxford Loan Agreement
Debt Instrument [Line Items]
Loan and security agreement, existing outstanding indebtedness								$ 20,000,000
Accrued interest rate						9.25%
Final payment fee, amount								$ 1,400,000
Oxford Midcap Loan
Debt Instrument [Line Items]
Loan and security agreement, existing outstanding indebtedness							$ 32,000,000
Accrued interest rate		9.25%		9.25%
Final payment fee, amount							$ 2,200,000
Repayments of debt	$ 19,100,000	$ 24,800,000
Proceeds from long-term debt			$ 12,700,000
Principal and interest payment amount				$ 1,000,000
Prepayment fee as percentage of outstanding principal amount				1.00%
Debt extinguished		27,300,000
Oxford EWB Loan
Debt Instrument [Line Items]
Loan and security agreement, existing outstanding indebtedness		$ 50,000,000		$ 50,000,000
Accrued interest rate		9.25%		9.25%
Final payment fee, amount		$ 3,800,000		$ 3,800,000
Proceeds from long-term debt		22,300,000
Principal and interest payment amount		1,900,000
Prepayment fee as percentage of outstanding principal amount				1.00%
Line of credit facility, additional advances limit		$ 20,000,000		$ 20,000,000
Line of credit facility, additional advances, number of tranches | tranche		2		2
Line of credit facility, additional advances, increase per tranche		$ 10,000,000		$ 10,000,000
Loss on early extinguishment of debt		1,300,000
Interest only payment amount		385,000
Fee for each additional $10 million advance		525,000		525,000
Debt instrument, covenant compliance, minimum restricted cash and certain eligible term investments threshold		10,000,000		$ 10,000,000
Additional default interest rate				5.00%
Unamortized balance of debt discount		3,800,000		$ 3,800,000
Deferred finance costs		$ 436,000		$ 436,000
Minimum
Debt Instrument [Line Items]
Capital lease expiration date				Oct. 1, 2017
Maximum
Debt Instrument [Line Items]
Capital lease expiration date				Jun. 1, 2019

Notes Payable - Future Minimum

Notes Payable - Future Minimum Payment Related Lease (Detail) $ in Thousands	Dec. 31, 2015USD ($)
Debt Instrument [Line Items]
Notes payable future minimum payments, 2016	$ 73
Notes payable future minimum payments, 2017	7,627
Notes payable future minimum payments, 2018	19,432
Notes payable future minimum payments, 2019	21,258
Notes payable future minimum payments, 2020	1,891
Total principal payments	$ 50,281

Revenue - Summary of Revenue Re

Revenue - Summary of Revenue Recognized (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenue [Line Items]
Revenue from Grants	$ 245	$ 539	$ 1,600
Small Business Innovative Research
Revenue [Line Items]
Revenue from Grants	245	539	630
Vulcan Incorporated
Revenue [Line Items]
Revenue from Grants	$ 0	$ 0	$ 970

Revenue - Additional Informatio

Revenue - Additional Information (Details) - USD ($)	1 Months Ended	12 Months Ended
	Oct. 31, 2010	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenue [Line Items]
Grant revenue recognized		$ 245,000	$ 539,000	$ 1,600,000
Reduction of equipment cost basis due to assets purchased with grant funding		0	80,000	0
Small Business Innovative Research
Revenue [Line Items]
Grant revenue recognized		245,000	539,000	630,000
Reduction of equipment cost basis due to assets purchased with grant funding		0	80,000	0
Remaining available amount under grant		219,000
Vulcan Incorporated
Revenue [Line Items]
Grant revenue recognized		$ 0	$ 0	970,000
Grants received	$ 20,000,000
Deferred revenue				$ 970,000

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail)	1 Months Ended		12 Months Ended
	Oct. 31, 2013USD ($)	Oct. 31, 2010USD ($)	Dec. 31, 2015USD ($)lease_extension	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)
Commitments and Contingencies Disclosure [Line Items]
Current Fiscal Year End Date			--12-31
Purchase Commitment, Remaining Minimum Amount Committed			$ 1,300,000
Remaining aggregate non-cancelable rent due			54,616,000
Research and development			48,379,000	$ 47,946,000	$ 36,297,000
Litigation settlement	$ 12,500,000
Selling, General and Administrative Expenses
Commitments and Contingencies Disclosure [Line Items]
Loss contingency accrual	$ 1,100,000
Maximum | Individual
Commitments and Contingencies Disclosure [Line Items]
Potential future payments			3,800,000
Stanley Medical Research Institute | Maximum
Commitments and Contingencies Disclosure [Line Items]
Potential future payments			12,800,000
Daiichi Sankyo Company Limited | One Indication
Commitments and Contingencies Disclosure [Line Items]
Potential future payments			23,500,000
Research and development					50,000
Daiichi Sankyo Company Limited | Maximum
Commitments and Contingencies Disclosure [Line Items]
Potential future payments			33,500,000
Helion Biotech ApS
Commitments and Contingencies Disclosure [Line Items]
Research and development				300,000	200,000
Helion Biotech ApS | Maximum
Commitments and Contingencies Disclosure [Line Items]
Potential future payments			6,100,000
Vulcan and Life Sciences Discovery Fund Authority
Commitments and Contingencies Disclosure [Line Items]
Potential future net proceeds		$ 1,500,000,000
Eligible expenses and expenditures deducted for computation of net proceeds			$ 25,000,000
Vulcan Incorporated
Commitments and Contingencies Disclosure [Line Items]
Amount payable under agreement		$ 25,000,000
Term of agreement		35 years
Life Sciences Discovery Fund Authority
Commitments and Contingencies Disclosure [Line Items]
Amount payable under agreement		$ 25,000,000
Building
Commitments and Contingencies Disclosure [Line Items]
Number of Options to extend the lease term | lease_extension			2
Options to extend the lease term, number of options			5 years
Remaining aggregate non-cancelable rent due			$ 54,500,000
Deferred rent			9,200,000
Rent expense			4,500,000	4,500,000	4,300,000
Sublease revenue			889,000	$ 568,000	$ 550,000
Equipment
Commitments and Contingencies Disclosure [Line Items]
Remaining aggregate non-cancelable rent due			$ 76,000

Commitments and Contingencies49

Commitments and Contingencies - Future Minimum Payment Related Lease (Detail) $ in Thousands	Dec. 31, 2015USD ($)
Lease Payments
2,016	$ 4,106
2,017	4,188
2,018	4,259
2,019	4,350
2,020	4,450
Thereafter	33,263
Total	54,616
Sublease Income
2,016	682
2,017	580
2,018	0
2,019	0
2,020	0
Thereafter	0
Total sublease income receivable	1,262
Net Lease Payments
2,016	3,424
2,017	3,608
2,018	4,259
2,019	4,350
2,020	4,450
Thereafter	33,263
Net operating lease payments	$ 53,354

Shareholders' Equity - Addition

Shareholders' Equity - Additional Information (Detail) - USD ($)	Jan. 01, 2016	Jan. 31, 2016	Feb. 28, 2015	Mar. 31, 2014	Oct. 31, 2013	May. 31, 2013	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Mar. 31, 2009
Class of Stock [Line Items]
Total shares reserved							10,784,472
Issuance of stock (in shares)			3,400,000	3,500,000		3,900,000
Share price (in USD per share)			$ 20.03	$ 11.50		$ 4.14
Exercise price of warrants (in USD per share)							$ 0.01			$ 12.25
Shares of common stock to purchase by warrant			749,250				749,250
Payment of stock issuance costs			$ 4,900,000	$ 2,500,000		$ 39,000
Proceeds from issuance of common stock and pre-funded warrants, net			$ 79,100,000	$ 37,800,000		$ 16,100,000	$ 79,076,000	$ 37,754,000	$ 20,988,000
Issuance of common stock utilizing At-The-Market Agreement					374,000
Stock offering program, weighted average price per share sold (in USD per share)					$ 13.29
Sales Agreement, Net Proceeds							$ 1,436,000	68,000	4,868,000
Warrant expiration date							Feb. 2, 2022
Fair Value Adjustment of Warrants								$ (863,000)	$ (41,000)
Stock Issued During Period, Shares, Other								28,653
Proceeds from Warrant Exercises							$ 1,400,000
Pre-funded warrants
Class of Stock [Line Items]
Share price (in USD per share)			$ 20.02
Exercise price of warrants (in USD per share)			$ 0.01
At The Market (ATM) Program | Subsequent Event
Class of Stock [Line Items]
Stock offering program, aggregate offering price		$ 100,000,000
Stock offering program, commission percent		1.70%
Stock offering program, notice period for termination		10 days
Equity Option | Subsequent Event | Equity Incentive Plan 2008
Class of Stock [Line Items]
Increase in authorized shares	1,785,714
Options granted and outstanding
Class of Stock [Line Items]
Total shares reserved							8,310,235
Options available for future grant
Class of Stock [Line Items]
Total shares reserved							1,724,987
Common stock warrants
Class of Stock [Line Items]
Total shares reserved							749,250
Common Stock
Class of Stock [Line Items]
Issuance of stock (in shares)							3,444,831	3,500,000	3,903,004
Issuance of common stock utilizing At-The-Market Agreement							133,240	28,653	373,700
Sales Agreement, Net Proceeds							$ 1,000	$ 0	$ 4,000

Shareholders' Equity - Reserved

Shareholders' Equity - Reserved Share of Common Stock (Detail)	Dec. 31, 2015shares
Reserved Common Stock [Line Items]
Total shares reserved	10,784,472
Options granted and outstanding
Reserved Common Stock [Line Items]
Total shares reserved	8,310,235
Options available for future grant
Reserved Common Stock [Line Items]
Total shares reserved	1,724,987
Common stock warrants
Reserved Common Stock [Line Items]
Total shares reserved	749,250

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($) $ in Thousands	Jan. 01, 2016	Feb. 29, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, maximum term			5 years 11 months 15 days	5 years 10 months 3 days	5 years 9 months 29 days
Shares granted in period			350,975
Non-employee options granted			4,200	86,000	40,000
Non-employee options, expense recognized			$ 492	$ 289	$ 71
Total intrinsic value of options exercised			$ 3,900	$ 2,900	$ 1,100
Unvested options outstanding			2,092,871
Unvested options outstanding, vesting period			2 years 1 month 13 days
Unrecognized compensation expense			$ 12,900
Equity Incentive Plan 2008
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, average vesting period			4 years
Annual increase provision, allowable percentage			5.00%
Annual increase provision, maximum allowable shares			1,785,714
Shares reserved for issuance			10,035,222
Shares available for grant			1,724,987
Equity Incentive Plan 2008 | Equity Option | Subsequent Event
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Increase in authorized shares	1,785,714
Equity Incentive Plan 2008 | Performance Shares | Subsequent Event
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted in period		1,269,000
Equity Incentive Plan 2008 | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options, maximum term			10 years

Stock-Based Compensation - Fair

Stock-Based Compensation - Fair Value of Employee Option Grant Estimated on Date of Grant (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Weighted-Average Assumptions
Estimated weighted-average fair value	$ 11.31	$ 7.39	$ 6.87
Expected volatility	71.00%	73.00%	88.00%
Expected term, in years	5 years 11 months 15 days	5 years 10 months 3 days	5 years 9 months 29 days
Risk-free interest rate	1.68%	1.87%	1.66%
Expected dividend yield	0.00%	0.00%	0.00%

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total	$ 9,581	$ 8,918	$ 6,252
Research and Development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	4,977	4,754	3,588
Selling, General and Administrative Expenses
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 4,604	$ 4,164	$ 2,664

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock Option Activity and Related Information (Detail) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015USD ($)$ / sharesshares
Options Outstanding
Beginning balance | shares	8,364,469
Granted | shares	350,975
Exercised | shares	(277,356)
Forfeited and expired | shares	(127,853)
Ending balance | shares	8,310,235
Vested and expected to vest | shares	8,096,339
Exercisable at December 31, 2015 | shares	6,217,364
Weighted-Average Exercise Price per Share
Beginning balance | $ / shares	$ 7.52
Granted | $ / shares	17.90
Exercised | $ / shares	5.13
Forfeited and expired | $ / shares	12.36
Ending balance | $ / shares	7.97
Vested and expected to vest | $ / shares	7.85
Exercisable at December 31, 2015 | $ / shares	$ 6.61
Weighted- Average Remaining Contractual Life
Balance at December 31, 2015	6 years 25 days
Vested and expected to vest	6 years
Exercisable at December 31, 2015	5 years 2 months 26 days
Aggregate Intrinsic Value
Balance at December 31, 2015 | $	$ 65,610
Vested and expected to vest | $	64,731
Exercisable at December 31, 2015 | $	$ 56,757

Stock-Based Compensation - Sto

Stock-Based Compensation - Stock Option Outstanding and Exercisable (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Number of Outstanding Shares	8,310,235	8,364,469
$0.98-$4.09
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price, Lower Range Limit	$ 0.98
Exercise Price, Upper Range Limit	$ 4.09
Options Outstanding, Number of Outstanding Shares	1,434,412
Options Outstanding, Weighted Average Remaining Life (Years)	1 year 25 days
Options Outstanding, Weighted Average Exercise Price	$ 1.17
Options Exercisable, Number Exercisable Shares	1,434,412
Options Exercisable, Weighted Average Exercise Price	$ 1.17
$4.10-$8.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price, Lower Range Limit	4.10
Exercise Price, Upper Range Limit	$ 8
Options Outstanding, Number of Outstanding Shares	1,975,794
Options Outstanding, Weighted Average Remaining Life (Years)	5 years 1 month 13 days
Options Outstanding, Weighted Average Exercise Price	$ 5.25
Options Exercisable, Number Exercisable Shares	1,958,011
Options Exercisable, Weighted Average Exercise Price	$ 5.23
$8.01-$11.42
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price, Lower Range Limit	8.01
Exercise Price, Upper Range Limit	$ 11.42
Options Outstanding, Number of Outstanding Shares	2,735,818
Options Outstanding, Weighted Average Remaining Life (Years)	7 years 2 months 1 day
Options Outstanding, Weighted Average Exercise Price	$ 9.79
Options Exercisable, Number Exercisable Shares	2,063,009
Options Exercisable, Weighted Average Exercise Price	$ 9.81
$11.43-$25.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price, Lower Range Limit	11.43
Exercise Price, Upper Range Limit	$ 21.49
Options Outstanding, Number of Outstanding Shares	2,164,211
Options Outstanding, Weighted Average Remaining Life (Years)	8 years 10 months 9 days
Options Outstanding, Weighted Average Exercise Price	$ 12.66
Options Exercisable, Number Exercisable Shares	761,932
Options Exercisable, Weighted Average Exercise Price	$ 11.73
$0.98-$25.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Price, Lower Range Limit	0.98
Exercise Price, Upper Range Limit	$ 21.49
Options Outstanding, Number of Outstanding Shares	8,310,235
Options Outstanding, Weighted Average Remaining Life (Years)	6 years 25 days
Options Outstanding, Weighted Average Exercise Price	$ 7.97
Options Exercisable, Number Exercisable Shares	6,217,364
Options Exercisable, Weighted Average Exercise Price	$ 6.61

Income Taxes - Significant Comp

Income Taxes - Significant Components of Deferred Tax Assets (Detail) - USD ($)	Dec. 31, 2015	Dec. 31, 2014
Deferred tax assets:
Net operating loss carryforwards	$ 110,092,000	$ 88,399,000
Tax credit carryforwards	14,758,000	9,569,000
Stock-based compensation	8,136,000	5,511,000
Deferred rent	3,324,000	3,077,000
Other	2,744,000	2,084,000
Total deferred tax assets	139,054,000	108,640,000
Less valuation allowance	(139,054,000)	(108,640,000)
Net deferred tax assets	0	0
Operating loss carryforwards	$ 325,900,000	$ 264,100,000

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Contingency [Line Items]
Operating loss carryforwards	$ 325,900	$ 264,100
Operating loss carryforward, state	30,600	100
Research and development tax credit	$ 14,758	9,569
Beginning year of net operating loss expiration	2,018
Ending year of net operating loss expiration	2,035
Deferred tax assets, percentage of valuation allowance	100.00%
Increase in deferred tax valuation allowance	$ 30,400	25,800	$ 14,500
Unrecognized Tax Benefits	212	$ 212	$ 212
Share Based Compensation
Income Tax Contingency [Line Items]
Operating loss carryforwards	$ 5,900

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Federal Statutory Tax Rate (Detail)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Statutory tax rate	(34.00%)	(34.00%)	(34.00%)
State tax rates	(2.00%)	0.00%	0.00%
Permanent difference	1.00%	2.00%	3.00%
Change in valuation allowance	41.00%	35.00%	36.00%
Tax credits	(5.00%)	(4.00%)	(5.00%)
Other	(1.00%)	1.00%	0.00%
Effective tax rate	0.00%	0.00%	0.00%

Quarterly Information (Unaudi60

Quarterly Information (Unaudited) - Quarterly Unaudited Statements of Operations (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Quarterly Financial Information Disclosure [Abstract]
Grant revenue	$ 6,675	$ 3,259	$ 3,187	$ 388	$ 180	$ 214	$ 45	$ 100	$ 13,509	$ 539	$ 1,600
Total operating expenses	24,715	22,560	19,154	18,318	20,155	17,346	17,262	15,784	84,747	70,547	52,116
Loss from operations	(18,040)	(19,301)	(15,967)	(17,930)	(19,975)	(17,132)	(17,217)	(15,684)	(71,238)	(70,008)	(50,516)
Net loss	$ (19,826)	$ (19,921)	$ (16,680)	$ (18,669)	$ (20,713)	$ (18,327)	$ (17,991)	$ (16,642)	$ (75,096)	$ (73,673)	$ (39,796)
Basic and diluted net loss per share	$ (0.52)	$ (0.53)	$ (0.44)	$ (0.51)	$ (0.61)	$ (0.54)	$ (0.53)	$ (0.54)	$ (2)	$ (2.22)	$ (1.39)

Quarterly Information (Unaudi61

Quarterly Information (Unaudited) - Additional Information (Detail) $ in Millions	1 Months Ended
	Oct. 31, 2013USD ($)
Quarterly Financial Information Disclosure [Abstract]
Litigation settlement	$ 12.5