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Document and Entity Information - USD ($)	12 Months Ended
Document and Entity Information - USD ($)	Dec. 31, 2019	Feb. 25, 2020	Jun. 30, 2019
Document Document and Entity Information [Abstract]
Document Type	10-K
Document Annual Report	true
Document Transition Report	false
Document Period End Date	Dec. 31, 2019
Entity File Number	001-34475
Entity Registrant Name	OMEROS CORPORATION
Entity Incorporation, State or Country Code	WA
Entity Tax Identification Number	91-1663741
Entity Address, Address Line One	201 Elliott Avenue West
Entity Address, City or Town	Seattle
Entity Address, State or Province	WA
Entity Address, Postal Zip Code	98119
City Area Code	206
Local Phone Number	676-5000
Title of 12(b) Security	Common Stock
Trading Symbol	OMER
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	Yes
Entity Common Stock, Shares Outstanding		54,205,177
Current Fiscal Year End Date	--12-31
Entity Public Float			$ 729,297,324
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Entity Central Index Key	0001285819
Amendment Flag	false

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 3,084	$ 5,861
Short-term investments	57,704	54,637
Receivables, net	35,185	22,818
Inventory	1,147	88
Prepaid expense and other assets	6,625	6,463
Total current assets	103,745	89,867
Property and equipment, net	3,829	3,845
Right of use assets	27,082
Restricted investments	1,154	1,154
Advanced payments, non-current	1,159	1,070
Total assets	136,969	95,936
Liabilities and shareholders' deficit
Accounts payable	5,328	6,281
Accrued expenses	46,627	30,186
Current portion of lease liabilities	3,504
Current portion of lease liabilities		889
Total current liabilities	55,459	37,356
Lease liabilities, non-current	32,318
Lease liabilities, non-current		1,578
Unsecured convertible senior notes, net	158,213	148,981
Deferred rent		8,177
Commitments and contingencies (Note 10)
Shareholders' deficit:
Preferred stock, par value $0.01 per share, 20,000,000 shares authorized; none issued and outstanding at December 31, 2019 and December 31, 2018.
Common stock, par value $0.01 per share, 150,000,000 shares authorized at December 31, 2019 and December 31, 2018; 54,200,810 and 49,011,684 shares issued and outstanding at December 31, 2019 and December 31, 2018, respectively.	542	490
Additional paid-in capital	625,048	549,479
Accumulated deficit	(734,611)	(650,125)
Total shareholders' deficit	(109,021)	(100,156)
Total liabilities and shareholders' deficit	$ 136,969	$ 95,936

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
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	54,200,810	49,011,684
Common stock, outstanding shares	54,200,810	49,011,684

CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues [Abstract]
Product sales, net	$ 111,805	$ 29,868	$ 64,826
Costs and expenses:
Cost of product sales	865	512	1,078
Research and development	109,696	89,860	55,599
Selling, general and administrative	64,626	51,718	52,044
Total costs and expenses	175,187	142,090	108,721
Loss from operations	(63,382)	(112,222)	(43,895)
Loss on early extinguishment of debt		(12,993)
Interest expense	(22,657)	(16,252)	(11,030)
Other income	1,553	1,781	1,444
Loss before income taxes	(84,486)	(139,686)	(53,481)
Income tax benefit	0	12,929	0
Net loss	(84,486)	(126,757)	(53,481)
Comprehensive loss	$ (84,486)	$ (126,757)	$ (53,481)
Basic and diluted net loss per share (USD per share)	$ (1.71)	$ (2.61)	$ (1.17)
Weighted-average shares used to compute basic and diluted net loss per share ( in shares)	49,523,444	48,582,636	45,539,362
Revenue, Product and Service [Extensible List]	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember
Cost, Product and Service [Extensible List]	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember

CONSOLIDATED STATEMENTS OF SHAREHOLDERS' DEFICIT - USD ($) $ in Thousands	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Total
Balance (in shares) at Dec. 31, 2016	43,819,133
Balance at Dec. 31, 2016	$ 438	$ 432,002	$ (469,887)	$ (37,447)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock in direct offering, net of offering costs	$ 30	63,627		63,657
Issuance of common stock in direct offering, net of offering costs (in shares)	3,000,000
Issuance of common stock upon exercise of stock options	$ 14	11,755		11,769
Issuance of common stock upon exercise of stock options (in shares)	1,392,093
Stock-based compensation		12,688		12,688
Net loss			(53,481)	(53,481)
Balance (in shares) at Dec. 31, 2017	48,211,226
Balance at Dec. 31, 2017	$ 482	520,072	(523,368)	(2,814)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options	$ 8	6,724		6,732
Issuance of common stock upon exercise of stock options (in shares)	800,458
Issuance of warrants in connection with debt amendment		1,424		1,424
Stock-based compensation		11,713		11,713
Premium paid for Capped Call in connection with Convertible Notes		(33,180)		(33,180)
Equity component of issuance of Convertible Notes		55,655		55,655
Tax benefit related to equity component of Convertible Notes		(12,929)		(12,929)
Net loss			(126,757)	(126,757)
Balance (in shares) at Dec. 31, 2018	49,011,684
Balance at Dec. 31, 2018	$ 490	549,479	(650,125)	(100,156)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock in direct offering, net of offering costs	$ 44	54,194		54,238
Issuance of common stock in direct offering, net of offering costs (in shares)	4,389,311
Issuance of common stock upon exercise of stock options	$ 8	7,590		$ 7,598
Issuance of common stock upon exercise of stock options (in shares)	799,815			799,815
Stock-based compensation		13,785		$ 13,785
Net loss			(84,486)	(84,486)
Balance (in shares) at Dec. 31, 2019	54,200,810
Balance at Dec. 31, 2019	$ 542	$ 625,048	$ (734,611)	$ (109,021)

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating activities:
Net loss	$ (84,486)	$ (126,757)	$ (53,481)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	13,785	11,713	12,688
Non-cash interest expense	9,232	5,635	4,187
Depreciation and amortization	1,790	962	551
Loss on early extinguishment of debt		12,993
Deferred income tax	0	(12,929)	0
Fair value adjustment to convertible notes in equity		354
Changes in operating assets and liabilities:
Receivables	(12,367)	(5,674)	(5,107)
Inventory	(1,059)	355	685
Prepaid expenses and other assets	(251)	(498)	(5,270)
Accounts payable and accrued expenses	13,283	10,109	9,520
Net cash used in operating activities	(60,073)	(103,737)	(36,227)
Investing activities:
Purchases of property and equipment	(334)	(567)	(350)
Purchases of investments	(58,217)	(68,782)	(65,326)
Proceeds from the sale and maturities of investments	55,150	94,500	28,078
Net cash (used in) provided by investing activities	(3,401)	25,151	(37,598)
Financing activities:
Proceeds from issuance of convertible senior notes		210,000
Proceeds from debt borrowings		44,550
Proceeds upon exercise of stock options and warrants	7,598	6,732	11,769
Proceeds from issuance of common stock, net	54,238		63,657
Release in restricted investments		4,681
Repayment of debt		(132,077)
Premium paid for capped call option		(33,180)
Payments on debt prepayment and extinguishment		(11,902)
Payments for debt issuance costs		(6,800)
Principal payments on finance lease liabilities	(1,139)
Principal payments on finance lease liabilities		(951)	(431)
Net cash provided by financing activities	60,697	81,053	74,995
Net (decrease) increase in cash and cash equivalents	(2,777)	2,467	1,170
Cash and cash equivalents at beginning of period	5,861	3,394	2,224
Cash and cash equivalents at end of period	3,084	5,861	3,394
Supplemental cash flow information
Cash paid for interest	13,462	8,896	6,895
Property acquired under finance lease	$ 1,440	2,118	1,141
Conversion of accrued interest to debt		3,408	$ 3,315
Fair value of warrants issued in connection with debt amendment		$ 1,424

Organization and Basis of Presentation

12 Months Ended

Dec. 31, 2019

Organization And Basis Of Presentation Disclosure [Abstract]

Organization and Basis of Presentation

Note 1—Organization and Basis of Presentation

Organization

We are a commercial-stage biopharmaceutical company committed to discovering, developing and commercializing small-molecule and protein therapeutics for large-market as well as orphan indications targeting inflammation, complement-mediated diseases, disorders of the central nervous system, and immune-related diseases, including cancers. Our first drug product, OMIDRIA, is marketed in the United States (U.S.) for use during cataract surgery or intraocular lens replacement.

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 U.S. generally accepted accounting principles (GAAP). Certain prior year amounts in the balance sheet, statement of cash flows and the footnotes have been reclassified in the consolidated financial statements to conform to the current year presentation.

Going Concern Discussion

As of December 31, 2019, we had cash, cash equivalents and investments of $60.8 million, net working capital of $48.3 million and an accounts receivable based line of credit that allows us to borrow up to $50.0 million depending on our eligible accounts receivable borrowing base. We have incurred losses from operations of $63.4 million, $112.2 million and $43.9 million in 2019, 2018 and 2017, respectively, used cash in operating activities of $60.1 million, $103.7 million and $36.2 million in 2019, 2018 and 2017, respectively and anticipate that we will continue to incur losses until such time as revenues exceed operating costs.

OMIDRIA pass-through reimbursement is scheduled to end on September 30, 2020. As such, we cannot predict with precision future OMIDRIA revenues due to the uncertain impact on sales of OMIDRIA in second half of 2020 and beyond. Similarly, we are unable to include in the determination regarding our prospects as a going concern amounts available under our revolving line of credit or any proceeds from debt transactions or other financing instruments despite our successful track record in accessing capital through these avenues. We also have not included any potential partnerships related to our products or product candidates. The conditions described above, when evaluated within the constraints of the accounting literature, raise substantial doubt with respect to our ability to meet our obligations through March 2, 2021 and, therefore, to continue as a going concern.

We plan to continue to fund our operations through proceeds from sales of OMIDRIA and, in addition, we may utilize funds available under our receivable-based line of credit, which allows us to borrow up to $50 million based on our available accounts-receivable borrowing base. Should it be necessary or determined to be strategically advantageous, we also could pursue debt financings, public and private offerings of our equity securities similar to those we have completed previously, and/or other strategic transactions, which may include licensing a portion of our existing technology. If these capital sources, for any reason, are needed but inaccessible, it would have a significantly negative effect on our financial condition. Should it be necessary to manage our operating expenses, we would reduce our projected cash requirements through reduction of our expenses by delaying clinical trials, reducing selected research and development efforts, and/or implementing other restructuring activities.

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

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, accruals for manufacturing of drug product, clinical drug supply and clinical trials, lease liabilities, and stock-based compensation expense. 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.

Significant Accounting Policies

12 Months Ended

Dec. 31, 2019

Accounting Policies [Abstract]

Significant Accounting Policies

Note 2—Significant Accounting Policies

Cash and Cash Equivalents, Short-Term Investments and Restricted 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. 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 investments are held in money-market funds.

As of December 31, 2019 and 2018, all investments are classified as short-term and available-for-sale. Investment income, which is included as a component of other income, consists primarily of interest earned.

Inventory

Inventory is stated at the lower of cost or market determined on a specific identification basis in a manner that 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). 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, Net

Receivables relate primarily to sales of OMIDRIA to wholesalers and include reductions for estimated chargebacks and product returns that are expected to be settled through reductions in receivables. Remaining receivables consist of amounts from subleases for space in our facilities. Considering the nature and historic collectability of our receivables, we concluded an allowance for doubtful accounts is not necessary as of December 31, 2019 and 2018.

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 10 years. Equipment acquired through finance 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 repairs and maintenance are expensed as incurred.

Right-of-Use Assets and Related Lease Liabilities

On January 1, 2019, we adopted Accounting Standards Update (ASU) 2016-02, Leases, (Topic 842) using a modified retrospective approach versus recasting the prior periods presented. We elected the package of practical expedients permitted under the transition guidance, which allowed us to carryforward our historical assessment of whether (i) contracts contain leases, (ii) lease classifications and (iii) initial direct costs. Upon adoption we recognized right-of-use assets and lease liabilities of $17.7 million and $26.4 million, respectively. The balance of the net right-of-use asset included the reversal of the outstanding balance of deferred rent of $8.7 million.

We record operating leases as right-of-use assets and recognize the related lease liabilities equal to the fair value of the lease payments using our incremental borrowing rate when the implicit rate in the lease agreement is not readily available. We recognize variable lease payments, when incurred. Costs associated with operating lease assets are recognized on a straight-line basis within operating expenses over the term of the lease.

We record finance leases as a component of property and equipment and amortize these assets within operating expenses on a straight-line basis to their residual values over the shorter of the term of the underlying lease or the estimated useful life of the equipment. The interest component of a finance lease is included in interest expense and recognized using the effective interest method over the lease term.

We account for leases with initial terms of 12 months or less as operating expenses on a straight-line basis over the lease term.

Impairment of Long-Lived Assets

We assess the impairment of long-lived assets, primarily property and equipment 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 that 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, 2019, 2018 and 2017.

Revenue Recognition

When we enter into a customer contract, we perform the following five steps: (i) identify the contract with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when (or as) we satisfy a performance obligation.

Product Sales, Net

We generally record revenue from product sales when the product is delivered to our wholesalers. Product sales are recorded net of wholesaler distribution fees and estimated chargebacks, rebates, returns and purchase-volume discounts. Accruals or allowances are established for these deductions in the same period 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 accounts receivable or as an accrued liability depending on how the amount is expected to be settled.

Chargebacks and Rebates: Provisions for chargebacks are determined utilizing historical and projected payer mix and information regarding sell-through and inventory on-hand 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 based on historical and projected patient claims. This experience ratio is applied to product sales to determine the patient rebate accrual and is being reviewed and updated periodically to reflect actual results.

We provide rebate payments for which ASCs qualify by meeting or exceeding purchase volumes of OMIDRIA under our purchase volume-discount program. We calculate rebate payment amounts due under this program based on actual qualifying purchase volumes and apply a contractual discount rate. For purchases of OMIDRIA not yet reported as sold-through to the ASC by our wholesalers, we apply an experience ratio to product sales to determine the rebate accrual. This experience ratio is being reviewed and updated periodically to reflect actual results.

Distribution Fees and Product Return Allowances: We pay our wholesalers a distribution fee for services that they perform for us based on the wholesaler average cost value of their purchases of OMIDRIA. We record a provision against product sales for these charges at the time of sale to the wholesaler.

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 return experience to date, the remaining shelf-life of product we have previously sold, inventory in the wholesale channel and our expectation that product is typically not held by the healthcare providers based on the frequency of their reorders.

Research and Development

Research and development expenses are comprised primarily of contracted research and manufacturing costs prior to approval; costs for personnel, including salaries, benefits and stock compensation; clinical study costs; contracted research; manufacturing costs prior to approval; consulting services; depreciation; materials and supplies; milestones; an allocation of our occupancy costs; and other expenses incurred to sustain our overall research and development programs. 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. All other research and development costs are expensed as incurred.

Selling, General and Administrative

Selling, general and administrative expenses are comprised primarily of salaries, benefits, and stock-compensation costs for sales, marketing, and other personnel not directly engaged in research and development. Additionally, selling, general and administrative expenses include marketing and selling expenses, professional and legal services; patent costs; depreciation, an allocation of our occupancy costs; and other general corporate expenses. Advertising costs, which we consider to be media and marketing materials, are expensed as incurred and were $8.0 million, $2.5 million and $0.3 million during the years ended December 31, 2019, 2018 and 2017, 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 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, which is generally the vesting period.

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, 2019, 2018 or 2017.

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 held at a financial institution may 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 our total revenues for the years ended December 31, 2019, 2018 and 2017 and greater than 10% of accounts receivable as of December 31, 2019, 2018 and 2017 as noted below.


	2019				2018				2017
	Percentage		Percentage		Percentage		Percentage		Percentage		Percentage
	of Total		of Accounts		of Total		of Accounts		of Total		of Accounts
	Revenue		Receivable		Revenue		Receivable		Revenue		Receivable
Distributor A	25	%	23	%	31	%	27	%	29	%	31	%
Distributor B	24	%	19	%	27	%	25	%	26	%	23	%
Distributor C	29	%	33	%	22	%	25	%	22	%	26	%
Distributor D	22	%	25	%	20	%	23	%	23	%	20	%

Major Suppliers

We use a single contract manufacturer to supply the OMIDRIA drug product and a separate company to package OMIDRIA for commercial sale. We generally use different contract manufacturers to produce drug substance, drug product and to perform final packaging for our drug product candidates.

We endeavor to maintain reasonable levels of drug supply for our commercial and clinical trial use and other manufacturers are available should we need to change suppliers. A change in suppliers, however, could cause a delay in delivery of OMIDRIA or our clinical trial material that would adversely affect our business.

Recent Accounting Pronouncements

In June 2016, the FASB issued ASU 2016-13, Financial Instruments—Credit Losses, (Topic 326) which changes how entities account for credit losses on most financial assets and certain other instruments and expands disclosures. The standard is effective for annual and interim periods beginning after December 15, 2019 with early adoption permitted. We adopted the standard on January 1, 2020 and the adoption did not have a material impact on our consolidated financial statements and disclosures.

In August 2018, the FASB issued ASU 2018-15, Intangibles—Goodwill and Other—Internal-Use Software, (Subtopic 350-40) related to the accounting for cloud computing arrangements to follow the internal-use software guidance in determining which development costs to defer and recognize as an asset. We adopted the standard January 1, 2020 on a prospective basis and expect to capitalize certain cloud computing development costs and amortize them on a straight-line basis over the expected useful-life of the related systems.

Net Loss Per Share

12 Months Ended

Dec. 31, 2019

Earnings Per Share [Abstract]

Net Loss Per Share

Note 3—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. Common share equivalents are excluded from the diluted net loss per share computations if their effect is anti-dilutive.

The basic and diluted net loss per share amounts for the years ended December 31, 2019, 2018 and 2017 were computed based on the shares of common stock outstanding during the respective periods. Potentially dilutive securities excluded from the diluted net loss per share calculation are as follows:


	Year Ended December 31,
	2019	2018	2017
Outstanding options to purchase common stock	11,207,931	10,313,138	9,657,259
Outstanding warrants to purchase common stock	243,115	243,115	100,602
Total potentially dilutive shares excluded from loss per share	11,451,046	10,556,253	9,757,861

Accounts Receivable, Net

12 Months Ended

Dec. 31, 2019

Receivables [Abstract]

Accounts Receivable, Net

Note 4—Accounts Receivable, Net

Accounts receivable, net consists of the following:


	December 31,
	2019		2018
	(In thousands)
Trade receivables, net	$	35,074	$	22,654
Sublease and other receivables		111		164
Total accounts receivables, net	$	35,185	$	22,818

Trade receivables are shown net of $1.6 million and $0.4 million of chargeback and product return allowances as of December 31, 2019 and 2018, respectively.

Fair-Value Measurements

12 Months Ended

Dec. 31, 2019

Fair Value Disclosures [Abstract]

Fair-Value Measurements

Note 5—Fair-Value Measurements

As of December 31, 2019 and 2018, all investments were classified as short-term and available-for-sale. Investment income, which was included as a component of other income, consists of interest earned.

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 measured at fair value on a recurring basis are as follows:


	December 31, 2019
	Level 1		Level 2		Level 3		Total
	(In thousands)
Assets:
Money-market funds classified as non-current restricted investments	$	1,154	$	—	$	—	$	1,154
Money-market funds classified as short-term investments		57,704		—		—		57,704
Total	$	58,858	$	—	$	—	$	58,858


	December 31, 2018
	Level 1		Level 2		Level 3		Total
	(In thousands)
Assets:
Money-market funds classified as non-current restricted investments	$	1,154	$	—	$	—	$	1,154
Money-market funds classified as short-term investments		54,637		—		—		54,637
Total	$	55,791	$	—	$	—	$	55,791

Cash held in demand deposit accounts of $3.1 million and $5.9 million is excluded from our fair-value hierarchy disclosure as of December 31, 2019 and 2018, respectively. There were no unrealized gains or losses associated with our short-term investments as of December 31, 2019 or 2018. The carrying amounts for receivables, accounts payable and accrued liabilities, and other current monetary assets and liabilities, including debt and lease financing obligations, approximate fair value.

See “Note 8--Convertible Senior Notes” for the carrying amount and estimated fair value of our 6.25% Convertible Senior Notes due 2023.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Certain Balance Sheet Accounts

12 Months Ended

Dec. 31, 2019

Receivables [Abstract]

Certain Balance Sheet Accounts

Note 6—Certain Balance Sheet Accounts

Inventory

Inventory consists of the following:


	December 31,		December 31,
	2019		2018
	(In thousands)
Raw materials	$	91	$	83
Work-in-progress		338		—
Finished goods		718		5
Total inventory	$	1,147	$	88

Property and Equipment, Net

Property and equipment, net consists of the following:


	December 31,
	2019		2018
	(In thousands)
Finance leases	$	5,474	$	4,034
Laboratory equipment		2,844		2,569
Computer equipment		921		862
Office equipment and furniture		625		625
Total cost		9,864		8,090
Less accumulated depreciation and amortization		(6,035)		(4,245)
Total property and equipment, net	$	3,829	$	3,845

For the years ended December 31, 2019, 2018 and 2017, depreciation and amortization expenses were $1.8 million, $1.0 million and $0.6 million, respectively.

Accrued Expenses

Accrued expenses consist of the following:


	December 31,
	2019		2018
	(In thousands)
Contract research and development	$	24,107	$	12,012
Sales rebates, fees and discounts		10,870		8,075
Consulting and professional fees		3,610		3,669
Employee compensation		3,546		2,714
Clinical trials		1,982		820
Interest payable		1,640		1,677
Other accrued expenses		872		1,219
Total accrued expenses	$	46,627	$	30,186

Debt

12 Months Ended

Dec. 31, 2019

Debt Disclosure [Abstract]

Debt

Note 7—Debt

Note Payable

In October 2016, we entered into a note payable agreement (the Note) and borrowed $80.0 million. In May 2018, we borrowed the remaining $45.0 million available under the Note and issued warrants to purchase up to 200,000 shares of our common stock with an exercise price of $23.00 per share and total fair value of $1.4 million.

Interest accrued on the Note at an annual rate of 12.25% (4.00% of which we deferred by adding such amounts to the aggregate principal amount outstanding). The Note required us to pay a back-end lender facility fee equal to 5.00% of the aggregate principal amount borrowed and, upon early repayment, we were subject to a 4.0% prepayment fee.

In November 2018, we issued $210.0 million in principal amount of unsecured convertible senior notes (see “Note 8--Convertible Senior Notes”) and repaid the Note. Upon repayment, we incurred a loss on early extinguishment of debt of $13.0 million associated with the unamortized lender facility fee, debt issuance costs, debt discount and prepayment fees upon repayment of the Note.

Line of Credit

In August 2019, we entered into a Loan and Security Agreement with Silicon Valley Bank, which provides for a $50.0 million revolving line of credit facility (the Line of Credit Agreement). Under the Line of Credit Agreement we may draw, on a revolving basis, up to the lesser of $50.0 million and 85.0% of our eligible accounts receivable, less certain reserves. The Line of Credit Agreement is secured by all our assets excluding intellectual property and development program inventories and matures in August 2022.

Interest on amounts outstanding is payable monthly at a floating rate equal to the greater of 5.50% and the prime rate per annum. If the Line of Credit Agreement is terminated prior to the maturity date for any reason other than replacement with a new Silicon Valley Bank (SVB) credit facility or a new syndicated facility in which SVB acts as the agent, we are required to pay a termination fee of $1.0 million. We paid an initial commitment fee of $150,000 upon closing and are required to pay additional commitment fees of $150,000 on each of the first and second anniversaries of the closing date, or upon the earlier termination of, or default under, the Line of Credit Agreement.

The Line of Credit Agreement requires a lockbox arrangement whereby our trade accounts receivable collections are deposited into a control account. Amounts deposited in the account are transferred daily to our operating account, except that during periods of reduced liquidity or upon an event of default, the amounts received in the control account are applied to reduce the outstanding obligations under the Line of Credit Agreement. The Line of Credit Agreement includes customary events of default that include, among other things, breach, non-payment, inaccuracy of representations and warranties, the occurrence of a material adverse change in our business or prospects for repayment of the Line of Credit, cross default to material indebtedness or material agreements, bankruptcy and insolvency, material judgments and a change in control. In the event of default, SVB may require all obligations under the Line of Credit Agreement to be immediately due and payable and charge a default rate of interest thereon. Additionally, under the loan and security agreement with SVB, we have agreed not to pay any dividends.

As of December 31, 2019, we had no outstanding borrowings under the Line of Credit Agreement.

Convertible Senior Notes

12 Months Ended

Dec. 31, 2019

Debt Disclosure [Abstract]

Convertible Senior Notes

Note 8—Convertible Senior Notes

In November 2018, we issued $210.0 million aggregate principal amount 6.25% Convertible Senior Notes due 2023 (the Convertible Notes) and received net proceeds of $24.0 million, as summarized below:


	(In thousands)
Convertible Notes initially issued	$	210,000
Repayment of previously outstanding loan		(146,046)
Purchase of Capped Call		(33,180)
Issuance costs		(6,800)
Net proceeds available for corporate use	$	23,974

The Convertible Notes accrue interest at an annual rate of 6.25% per annum, payable semi-annually in arrears on May 15 and November 15 of each year, beginning on May 15, 2019. The Convertible Notes mature on November 15, 2023, unless earlier repurchased, redeemed or converted in accordance with their terms and are unsecured.

The Convertible Notes will be convertible into cash, shares of our common stock or a combination thereof, as we elect at our sole discretion. The initial conversion rate is 52.0183 shares of our common stock per $1,000 of note principal (equivalent to an initial conversion price of approximately $19.22 per share of common stock), subject to adjustment in certain circumstances.

The Convertible Notes will be convertible at the option of the holders on or after May 15, 2023 at any time prior to the close of business on the second scheduled trading day immediately preceding the stated maturity date of

November 15, 2023. Additionally, holders may convert their Convertible Notes at their option at specified times prior to the maturity date of November 15, 2023, only if:

(1)

during any calendar quarter beginning after March 31, 2019, the last reported sale price per share of our common stock exceeds 130% of the conversion price of the Convertible Notes for each of at least 20 trading days in the period of 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter;

(2)

during the five consecutive business days immediately after any five-consecutive-trading-day period (such five-consecutive-trading-day period, the “measurement period”) in which the trading price per $1,000 principal amount of Convertible Notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price per share of our common stock on such trading day and the conversion rate on such trading day;

(3)

upon the occurrence of certain corporate events or distributions of our common stock; or

(4)

we call the Convertible Notes for redemption.

Subject to the satisfaction of certain conditions, we may redeem all, but not less than all, of the Convertible Notes at our option prior to the maturity date at a cash redemption price equal to the principal amount of the Convertible Notes to be redeemed, plus any accrued and unpaid interest. The Convertible Notes are subject to redemption only if certain requirements are satisfied, including that the last reported sale price per share of our common stock exceeds 150% of the conversion price on (i) each of at least 20 trading days, whether or not consecutive, during the 30 consecutive trading days ending on, and including, the trading day immediately before the date we send the related redemption notice and (ii) the trading day immediately before the date we send such notice.

In order to reduce the dilutive impact or potential cash expenditure associated with conversion of the Convertible Notes, we used $33.2 million of the proceeds from sale of the Convertible Notes to enter into a capped call transaction (the Capped Call Transaction). The Capped Call Transaction will cover, subject to anti-dilution adjustments substantially similar to those applicable to the Convertible Notes, the number of shares of our common stock underlying the Convertible Notes when our common stock is trading between the initial conversion price of approximately $19.22 and $28.8360. However, if the market price of our common stock exceeds the $28.8360 cap price, then the conversion of the Convertible Notes would have a dilutive impact and/or require a cash expenditure to the extent the market price exceeds the cap price.

We evaluated the accounting for the issuance of the Convertible Notes and concluded that the embedded conversion features meet the requirements for a derivative scope exception for instruments that are both indexed to an entity’s own stock and classified in stockholders’ equity in its balance sheet, and that the cash conversion guidance applies. Therefore, the Convertible Notes issuance proceeds of $210.0 million are allocated first to the liability component based on the fair value of non-convertible debt with otherwise identical residual terms with the residual proceeds allocated to equity for the conversion features. The debt issuance costs associated with the Convertible Notes of $6.8 million were allocated to the liability and equity component in the same proportion as the issuance proceeds. We also evaluated the interest feature on default and redemption features embedded in the Convertible Notes and concluded that they are clearly and closely related to the Convertible Notes, and therefore they would not be separately accounted for as a derivative. For the contingent interest features unrelated to our creditworthiness, we concluded that they should be separately accounted for as a compound derivative instrument with de-minimis value. Further, we concluded the Capped Call Transaction qualifies for a derivative scope exception for instruments that are both indexed to an entity’s own stock and classified in stockholders’ equity in its balance sheet. Consequently, the fair value of the Capped Call of $33.2 million is classified as equity and will not be subsequently remeasured.

The balance of our Convertible Notes at December 31, 2019 and 2018, is as follows:


	December 31,		December 31,
	2019		2018
	(In thousands)
Principal amount	$	210,000	$	210,000
Unamortized discount		(47,660)		(56,156)
Unamortized issuance costs attributable to principal amount		(4,127)		(4,863)
Total Convertible Notes, net	$	158,213	$	148,981
Fair value of outstanding Convertible Notes	$	208,163	$	186,900
Amount by which the Convertible Notes if-converted value exceeds their principal amount	$	—	$	—

The unamortized debt discount and debt issuance costs related to the Convertible Notes are being amortized to interest expense using the effective interest method through the scheduled maturity of November 15, 2023.

The estimated fair value of the Convertible Notes at December 31, 2019, as determined through consideration of quoted market prices, was $208.2 million. The fair value is classified as Level 3 due to the limited trading activity for the Convertible Notes.

Lease Liabilities

12 Months Ended

Dec. 31, 2019

Leases [Abstract]

Lease liabilities

Note 9—Lease Liabilities

We have operating leases related to our office and laboratory space. The initial term of the leases is through November 2027 and we have two options to extend the lease term, each by five years. We have finance leases for certain laboratory and office equipment that have lease terms expiring through December 2023.

As described further in “Note 2--Significant Accounting Policies”, on January 1, 2019, we adopted ASU 2016-02, Leases, (Topic 842) using a modified retrospective approach versus recasting the prior periods presented. The lease-related assets and liabilities recorded on the balance sheet are as follows. Prior year financial statements were not recast under the new standard and, therefore, those amounts are not presented below.


	Classification on the Balance Sheet	December 31, 2019
Assets		(In thousands)
Operating lease assets	Right of use assets	$	27,082
Finance lease assets	Property and equipment, net		2,973
Total lease assets		$	30,055

Liabilities
Current:
Operating leases	Current portion of lease liabilities	$	2,282
Finance leases	Current portion of lease liabilities		1,222
Non-current:
Operating leases	Lease liabilities, non-current		30,772
Finance leases	Lease liabilities, non-current		1,546
Total lease liabilities		$	35,822

Weighted-average remaining lease term
Operating leases			7.8 years
Finance leases			2.5 years
Weighted-average discount rate
Operating leases			12.85	%
Finance leases			12.17	%

The components of total lease costs are as follows:


	Year Ended
	December 31, 2019
	(In thousands)
Lease cost
Operating lease cost	$	4,604
Finance lease cost:
Amortization		1,340
Interest		337
Short-term lease cost		275
Variable lease cost		2,045
Sublease income		(913)
Total lease cost	$	7,688

The supplemental cash flow information related to leases during 2019 is as follows:


Cash paid for amounts included in the measurement of lease liabilities
Operating cash flows used for operating leases	$	6,951
Operating cash flows used for finance leases	$	337
Financing cash flows used for finance leases	$	1,139

The future maturities of our lease liabilities as of December 31, 2019 are as follows:


	Operating		Finance
	Leases		Leases
	(In thousands)
2020	$	6,398	$	1,434
2021		6,536		1,076
2022		6,678		490
2023		6,823		131
2024		6,972		27
Thereafter		19,590		—
Total undiscounted lease payments		52,997		3,158
Less interest		19,943		390
Lease liabilities	$	33,054	$	2,768

In 2019, we leased additional office and laboratory space in our headquarters building, which qualified as an operating lease, and recorded additional right-of-use assets and lease liabilities of $10.4 million.

Commitments and Contingencies

12 Months Ended

Dec. 31, 2019

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

Note 10—Commitments and Contingencies

Contracts

We have various agreements with third parties that collectively require payment of termination fees totaling $22.7 million as of December 31, 2019 if we cancel the work within specific time frames, either prior to commencing or during performance of the contracted services.

Development Milestones and Product Royalties

We have licensed a variety of intellectual property from third parties that we are currently developing or may develop in the future. These licenses may require milestone payments during the clinical development processes as well as low single to low double-digit royalties on the net income or net sales of the product. For the years ended

December 31, 2019, 2018 and 2017, development milestones incurred were immaterial and we did not owe any royalties.

Shareholders' Equity

12 Months Ended

Dec. 31, 2019

Equity [Abstract]

Shareholders' Equity

Note 11—Shareholders’ Equity

Common Stock

As of December 31, 2019, we had reserved shares of common stock for the following purposes:


Options granted and outstanding		11,207,931
Options available for future grant		5,397,602
Common stock warrants		243,115
Total shares reserved		16,848,648

Securities Offerings – In December 2019, we sold 4.4 million shares of our common stock at a public offering price of $13.10 per share. After deducting underwriter discounts and offering expense, we received net proceeds from the transaction of $54.2 million.

In August 2017, we sold 3.0 million shares of our common stock at a public offering price of $22.75 per share. After deducting underwriter discounts and offering expenses, we received net proceeds from the transaction of $63.6 million.

Warrants

In connection with various previously outstanding debt agreements we have issued warrants to purchase shares of our common stock as follows:


Outstanding At
December 31, 2019	Expiration Date	Exercise Price
43,115	May 18, 2023	$	9.94
200,000	April 12, 2023	$	23.00

Stock-Based Compensation

12 Months Ended

Dec. 31, 2019

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Stock-Based Compensation

Note 12—Stock-Based Compensation

Our stock option plans provide for the grant of incentive and non-statutory stock options, stock appreciation rights, restricted stock, restricted stock units, performance units, performance shares and other stock and cash awards to employees, directors and consultants and subsidiary corporations’ employees and consultants. Stock options must be granted with exercise prices not less than the fair market value of the common stock subject to the stock option on the date of the grant and the options may not exceed 10 years. Any unvested stock options granted which are subsequently canceled become available for future grant.

As of December 31, 2019, a total of 16.9 million shares were reserved for issuance under our stock plans and outstanding warrants, of which 5.4 million were available for future grants which includes shares registered in June 2019 under the Omeros Corporation 2017 Omnibus Incentive Compensation Plan, as amended and restated effective June 7, 2019. [In March 2020, annual stock option grants totaling approximately 1.6 million shares with an exercise price of $11.91 per share were granted to all eligible employees. The options vest monthly on a straight-line basis over four years.]

Stock-based compensation expense is as follows:


	Year Ended December 31,
	2019		2018		2017
	(In thousands)
Research and development	$	6,095	$	4,961	$	5,240
Selling, general and administrative		7,690		6,752		7,448
Total	$	13,785	$	11,713	$	12,688

The fair value of each option grant is estimated on the date of grant using the Black-Scholes option-pricing model. The following assumptions were applied to stock option grants during the periods ended:


	Year Ended December 31,
	2019			2018			2017
Estimated weighted-average fair value	$	9.93		$	10.32		$	8.66
Weighted-average assumptions:
Expected volatility		80	%		78	%		74	%
Expected term, in years		6.0			6.0			6.0
Risk-free interest rate		2.41	%		2.68	%		2.05	%
Expected dividend yield		—	%		—	%		—	%

During the years ended December 31, 2019 and 2018, we granted to non-employees options to purchase 20,000 shares and 20,000 shares of common stock, respectively. In connection with the non-employee options, we recognized expense of $0.2 million, $0.2 million, and $0.5 million during the years ended December 31, 2019, 2018 and 2017, respectively.

Stock option activity for all stock plans is as follows:


		Weighted-
		Average			Aggregate
		Exercise		Remaining	Intrinsic
	Options	Price per		Contractual Life	Value
	Outstanding	Share		(In years)	(In thousands)
Balance at December 31, 2018	10,313,138	$	11.22
Granted	2,098,705		14.23
Exercised	(799,815)		9.50
Forfeited	(404,097)		16.28
Balance at December 31, 2019	11,207,931	$	11.72	6.0	$	31,912
Vested and expected to vest at December 31, 2019	10,876,043	$	11.65	6.0	$	31,661
Exercisable at December 31, 2019	8,212,177	$	10.87	5.1	$	29,546

The total intrinsic value of options exercised during the years ended December 31, 2019, 2018 and 2017 was $5.4 million, $11.4 million and $16.4 million, respectively.

At December 31, 2019, there were 3.0 million unvested options outstanding that will vest over a weighted-average period of 2.6 years. The remaining estimated compensation expense to be recognized in connection with these unvested options is $24.2 million.

Income Taxes

12 Months Ended

Dec. 31, 2019

Income Tax Disclosure [Abstract]

Income Taxes

Note 13—Income Taxes

The components of income tax benefit are as follows:


	December 31,
	2019		2018		2017
	(In thousands)
Current income tax benefit:
Federal	$	—	$	—	$	—
State		—		—		—
Total current income tax benefit		—		—		—
Deferred income tax benefit:
Federal		—		11,261		—
State		—		1,668		—
Total deferred income tax benefit		—		12,929		—
Income tax benefit	$	—	$	12,929	$	—

We have a history of losses and therefore have historically not made a provision for income taxes. However, in 2018 we recorded an income tax benefit of $12.9 million related to the issuance of our Convertible Notes. In accordance with intra-period tax allocation rules, the deferred tax liability related to the equity component of convertible debt is a source of income that can be used to recognize the tax benefit of the current year loss through continuing operations. The tax benefit related to the issuance of our Convertible Notes occurred in 2018 and does not recur in subsequent years. 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 income taxes are as follows:


	December 31,
	2019		2018
	(In thousands)
Deferred tax assets:
Net operating loss carryforwards	$	126,794	$	113,928
Research and development tax credits		40,654		35,739
Stock-based compensation		9,959		8,969
Deferred rent		—		2,037
Lease liability		7,908		—
Other		14,555		10,413
Total deferred tax assets		199,870		171,086
Deferred tax liabilities:
Equity component of Convertible Notes		(11,082)		(12,706)
Right of use assets		(6,480)		—
Total deferred tax liabilities		(17,562)		(12,706)
Net deferred tax assets before valuation allowance		182,308		158,380
Less valuation allowance		(182,308)		(158,380)
Net deferred tax assets	$	—	$	—

As of December 31, 2019 and 2018, we had federal net operating loss carryforwards of approximately $564.3 million and $513.2 million, respectively, and state net operating losses of approximately $170.5 million and $125.0 million, respectively.

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 2020 and 2039.

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 $23.9 million and $26.4 million in 2019 and 2018, 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,
	2019		2018		2017
U.S. Federal statutory rate on net loss	(21)	%	(21)	%	(34)	%
State tax, net of federal tax benefit	(2)	%	(2)	%	(2)	%
Effects of statutory rate change	—	%	—	%	115	%
Change in valuation allowance	28	%	19	%	(60)	%
Tax credits	(6)	%	(5)	%	(11)	%
Other	1	%	—	%	(8)	%
Effective tax rate	—	%	(9)	%	—	%

We file federal and certain 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.

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.

401k Retirement Plan

12 Months Ended

Dec. 31, 2019

Retirement Benefits [Abstract]

401(k) Retirement Plan

Note 14—401(k) Retirement Plan

Our 401(k) retirement plan provides for an annual company discretionary match on employee contributions up to 4.0% of each participating employee’s eligible earnings, with a maximum company match of $4,000 per employee per year. All employees are eligible to participate.

Quarterly Information (Unaudited)

12 Months Ended

Dec. 31, 2019

Quarterly Financial Information Disclosure [Abstract]

Quarterly Information (Unaudited)

Note 15—Quarterly Information (Unaudited)

The following table summarizes the unaudited statements of operations and comprehensive loss for each quarter of 2019 and 2018 (in thousands, except per share amounts):


2019	For the Quarter Ended
		March 31,		June 30,		September 30,		December 31,
Revenue (1)	$	21,779	$	26,753	$	29,856	$	33,417
Total costs and expenses		41,018		36,091		40,957		57,121
Loss from operations		(19,239)		(9,338)		(11,101)		(23,704)
Net loss		(24,345)		(14,453)		(16,463)		(29,225)
Basic and diluted net loss per share	$	(0.50)	$	(0.29)	$	(0.33)	$	(0.58)


2018	For the Quarter Ended
		March 31,		June 30,		September 30,		December 31,
Revenue	$	1,588	$	1,655	$	4,608	$	22,017
Total costs and expenses		29,277		32,272		40,050		40,491
Loss from operations		(27,689)		(30,617)		(35,442)		(18,474)
Net loss		(30,054)		(33,696)		(39,472)		(23,534)
Basic and diluted net loss per share	$	(0.62)	$	(0.70)	$	(0.81)	$	(0.48)

(1)

As further described in Note 1, OMIDRIA was reimbursed under Medicare Part B from January 1, 2015 through December 31, 2017. For the period January 1, 2018 through September 30, 2018, OMIDRIA was not reimbursed separately for procedures covered under Medicare Part B. Beginning October 1, 2018, OMIDRIA was again reimbursed separately under Medicare Part B.

Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2019

Accounting Policies [Abstract]

Organization

Basis of Presentation

Segment

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

Cash and Cash Equivalents, Short-Term Investments and Restricted Investments

Inventory

Receivables, Net

Property and Equipment, Net

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 repairs and maintenance are expensed as incurred.

Right-of-Use Assets and Related Lease Liabilities

Right-of-Use Assets and Related Lease Liabilities

We account for leases with initial terms of 12 months or less as operating expenses on a straight-line basis over the lease term.

Impairment of Long-Lived Assets

Revenue Recognition

Product Sales, Net

Chargeback and Rebates

Distribution Fees and Product Return Allowances

Research and Development

Research and Development

Selling, General and Administrative

Income Taxes

Stock-Based Compensation

compensation cost to reporting periods over each optionee’s requisite service period, which is generally the vesting period.

Accumulated Other Comprehensive Loss

Financial Instruments and Concentrations of Credit Risk

Major Customers


	2019				2018				2017
	Percentage		Percentage		Percentage		Percentage		Percentage		Percentage
	of Total		of Accounts		of Total		of Accounts		of Total		of Accounts
	Revenue		Receivable		Revenue		Receivable		Revenue		Receivable
Distributor A	25	%	23	%	31	%	27	%	29	%	31	%
Distributor B	24	%	19	%	27	%	25	%	26	%	23	%
Distributor C	29	%	33	%	22	%	25	%	22	%	26	%
Distributor D	22	%	25	%	20	%	23	%	23	%	20	%

Major Suppliers

Recent Accounting Pronouncements

Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2019

Accounting Policies [Abstract]

Schedule of Revenue by Major Customers by Reporting Segments


	2019				2018				2017
	Percentage		Percentage		Percentage		Percentage		Percentage		Percentage
	of Total		of Accounts		of Total		of Accounts		of Total		of Accounts
	Revenue		Receivable		Revenue		Receivable		Revenue		Receivable
Distributor A	25	%	23	%	31	%	27	%	29	%	31	%
Distributor B	24	%	19	%	27	%	25	%	26	%	23	%
Distributor C	29	%	33	%	22	%	25	%	22	%	26	%
Distributor D	22	%	25	%	20	%	23	%	23	%	20	%

Net Loss Per Share (Tables)

12 Months Ended

Dec. 31, 2019

Earnings Per Share [Abstract]

Calculation of Historical Outstanding Dilutive Securities Not Included in Diluted Loss per Share


	Year Ended December 31,
	2019	2018	2017
Outstanding options to purchase common stock	11,207,931	10,313,138	9,657,259
Outstanding warrants to purchase common stock	243,115	243,115	100,602
Total potentially dilutive shares excluded from loss per share	11,451,046	10,556,253	9,757,861

Accounts Receivable, Net (Tables)

12 Months Ended

Dec. 31, 2019

Receivables [Abstract]

Schedule of accounts receivable


	December 31,
	2019		2018
	(In thousands)
Trade receivables, net	$	35,074	$	22,654
Sublease and other receivables		111		164
Total accounts receivables, net	$	35,185	$	22,818

Fair-Value Measurements (Tables)

12 Months Ended

Dec. 31, 2019

Fair Value Disclosures [Abstract]

Financial Assets and Liabilities Measured at Fair Value on Recurring Basis


	December 31, 2019
	Level 1		Level 2		Level 3		Total
	(In thousands)
Assets:
Money-market funds classified as non-current restricted investments	$	1,154	$	—	$	—	$	1,154
Money-market funds classified as short-term investments		57,704		—		—		57,704
Total	$	58,858	$	—	$	—	$	58,858


	December 31, 2018
	Level 1		Level 2		Level 3		Total
	(In thousands)
Assets:
Money-market funds classified as non-current restricted investments	$	1,154	$	—	$	—	$	1,154
Money-market funds classified as short-term investments		54,637		—		—		54,637
Total	$	55,791	$	—	$	—	$	55,791

Certain Balance Sheet Accounts (Tables)

12 Months Ended

Dec. 31, 2019

Receivables [Abstract]

Schedule of Inventory, Current


	December 31,		December 31,
	2019		2018
	(In thousands)
Raw materials	$	91	$	83
Work-in-progress		338		—
Finished goods		718		5
Total inventory	$	1,147	$	88

Property, Plant and Equipment


	December 31,
	2019		2018
	(In thousands)
Finance leases	$	5,474	$	4,034
Laboratory equipment		2,844		2,569
Computer equipment		921		862
Office equipment and furniture		625		625
Total cost		9,864		8,090
Less accumulated depreciation and amortization		(6,035)		(4,245)
Total property and equipment, net	$	3,829	$	3,845

Accrued Expenses


	December 31,
	2019		2018
	(In thousands)
Contract research and development	$	24,107	$	12,012
Sales rebates, fees and discounts		10,870		8,075
Consulting and professional fees		3,610		3,669
Employee compensation		3,546		2,714
Clinical trials		1,982		820
Interest payable		1,640		1,677
Other accrued expenses		872		1,219
Total accrued expenses	$	46,627	$	30,186

Convertible Senior Notes (Tables)

12 Months Ended

Dec. 31, 2019

Debt Disclosure [Abstract]

Convertible Debt


	(In thousands)
Convertible Notes initially issued	$	210,000
Repayment of previously outstanding loan		(146,046)
Purchase of Capped Call		(33,180)
Issuance costs		(6,800)
Net proceeds available for corporate use	$	23,974


	December 31,		December 31,
	2019		2018
	(In thousands)
Principal amount	$	210,000	$	210,000
Unamortized discount		(47,660)		(56,156)
Unamortized issuance costs attributable to principal amount		(4,127)		(4,863)
Total Convertible Notes, net	$	158,213	$	148,981
Fair value of outstanding Convertible Notes	$	208,163	$	186,900
Amount by which the Convertible Notes if-converted value exceeds their principal amount	$	—	$	—

Lease Liabilities (Tables)

12 Months Ended

Dec. 31, 2019

Leases [Abstract]

Schedule of lease-related assets and liabilities recorded on the balance sheet


	Classification on the Balance Sheet	December 31, 2019
Assets		(In thousands)
Operating lease assets	Right of use assets	$	27,082
Finance lease assets	Property and equipment, net		2,973
Total lease assets		$	30,055

Liabilities
Current:
Operating leases	Current portion of lease liabilities	$	2,282
Finance leases	Current portion of lease liabilities		1,222
Non-current:
Operating leases	Lease liabilities, non-current		30,772
Finance leases	Lease liabilities, non-current		1,546
Total lease liabilities		$	35,822

Weighted-average remaining lease term
Operating leases			7.8 years
Finance leases			2.5 years
Weighted-average discount rate
Operating leases			12.85	%
Finance leases			12.17	%

Schedule of lease costs


	Year Ended
	December 31, 2019
	(In thousands)
Lease cost
Operating lease cost	$	4,604
Finance lease cost:
Amortization		1,340
Interest		337
Short-term lease cost		275
Variable lease cost		2,045
Sublease income		(913)
Total lease cost	$	7,688

Schedule of supplemental cash flow information


Cash paid for amounts included in the measurement of lease liabilities
Operating cash flows used for operating leases	$	6,951
Operating cash flows used for finance leases	$	337
Financing cash flows used for finance leases	$	1,139

Schedule of operating and finance lease liability


	Operating		Finance
	Leases		Leases
	(In thousands)
2020	$	6,398	$	1,434
2021		6,536		1,076
2022		6,678		490
2023		6,823		131
2024		6,972		27
Thereafter		19,590		—
Total undiscounted lease payments		52,997		3,158
Less interest		19,943		390
Lease liabilities	$	33,054	$	2,768

Shareholders' Equity (Tables)

12 Months Ended

Dec. 31, 2019

Equity [Abstract]

Reserved Shares of Common Stock


Options granted and outstanding		11,207,931
Options available for future grant		5,397,602
Common stock warrants		243,115
Total shares reserved		16,848,648

Schedule of Stockholders' Equity Note, Warrants or Rights


Outstanding At
December 31, 2019	Expiration Date	Exercise Price
43,115	May 18, 2023	$	9.94
200,000	April 12, 2023	$	23.00

Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2019

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Stock-Based Compensation Expense


	Year Ended December 31,
	2019		2018		2017
	(In thousands)
Research and development	$	6,095	$	4,961	$	5,240
Selling, general and administrative		7,690		6,752		7,448
Total	$	13,785	$	11,713	$	12,688

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions


	Year Ended December 31,
	2019			2018			2017
Estimated weighted-average fair value	$	9.93		$	10.32		$	8.66
Weighted-average assumptions:
Expected volatility		80	%		78	%		74	%
Expected term, in years		6.0			6.0			6.0
Risk-free interest rate		2.41	%		2.68	%		2.05	%
Expected dividend yield		—	%		—	%		—	%

Schedule of Stock Option Activity


		Weighted-
		Average			Aggregate
		Exercise		Remaining	Intrinsic
	Options	Price per		Contractual Life	Value
	Outstanding	Share		(In years)	(In thousands)
Balance at December 31, 2018	10,313,138	$	11.22
Granted	2,098,705		14.23
Exercised	(799,815)		9.50
Forfeited	(404,097)		16.28
Balance at December 31, 2019	11,207,931	$	11.72	6.0	$	31,912
Vested and expected to vest at December 31, 2019	10,876,043	$	11.65	6.0	$	31,661
Exercisable at December 31, 2019	8,212,177	$	10.87	5.1	$	29,546

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2019

Income Tax Disclosure [Abstract]

Schedule of Components of Income Tax Expense (Benefit)


	December 31,
	2019		2018		2017
	(In thousands)
Current income tax benefit:
Federal	$	—	$	—	$	—
State		—		—		—
Total current income tax benefit		—		—		—
Deferred income tax benefit:
Federal		—		11,261		—
State		—		1,668		—
Total deferred income tax benefit		—		12,929		—
Income tax benefit	$	—	$	12,929	$	—

Significant Components of Deferred Tax Assets


	December 31,
	2019		2018
	(In thousands)
Deferred tax assets:
Net operating loss carryforwards	$	126,794	$	113,928
Research and development tax credits		40,654		35,739
Stock-based compensation		9,959		8,969
Deferred rent		—		2,037
Lease liability		7,908		—
Other		14,555		10,413
Total deferred tax assets		199,870		171,086
Deferred tax liabilities:
Equity component of Convertible Notes		(11,082)		(12,706)
Right of use assets		(6,480)		—
Total deferred tax liabilities		(17,562)		(12,706)
Net deferred tax assets before valuation allowance		182,308		158,380
Less valuation allowance		(182,308)		(158,380)
Net deferred tax assets	$	—	$	—

Reconciliation of Federal Statutory Tax Rate to Effective Income Tax


	Year ended December 31,
	2019		2018		2017
U.S. Federal statutory rate on net loss	(21)	%	(21)	%	(34)	%
State tax, net of federal tax benefit	(2)	%	(2)	%	(2)	%
Effects of statutory rate change	—	%	—	%	115	%
Change in valuation allowance	28	%	19	%	(60)	%
Tax credits	(6)	%	(5)	%	(11)	%
Other	1	%	—	%	(8)	%
Effective tax rate	—	%	(9)	%	—	%

Quarterly Information (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2019

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 2019 and 2018 (in thousands, except per share amounts):


2019	For the Quarter Ended
		March 31,		June 30,		September 30,		December 31,
Revenue (1)	$	21,779	$	26,753	$	29,856	$	33,417
Total costs and expenses		41,018		36,091		40,957		57,121
Loss from operations		(19,239)		(9,338)		(11,101)		(23,704)
Net loss		(24,345)		(14,453)		(16,463)		(29,225)
Basic and diluted net loss per share	$	(0.50)	$	(0.29)	$	(0.33)	$	(0.58)


2018	For the Quarter Ended
		March 31,		June 30,		September 30,		December 31,
Revenue	$	1,588	$	1,655	$	4,608	$	22,017
Total costs and expenses		29,277		32,272		40,050		40,491
Loss from operations		(27,689)		(30,617)		(35,442)		(18,474)
Net loss		(30,054)		(33,696)		(39,472)		(23,534)
Basic and diluted net loss per share	$	(0.62)	$	(0.70)	$	(0.81)	$	(0.48)

Organization and Basis of Presentation - Additional Information (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2019 USD ($) segment	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Aug. 31, 2019 USD ($)
Organization And Basis Of Presentation [Line Items]
Cash, cash equivalents and marketable securities	$ 60,800								$ 60,800
Net Working Capital Adjustments	48,300								48,300
Operating Income (Loss)	23,704	$ 11,101	$ 9,338	$ 19,239	$ 18,474	$ 35,442	$ 30,617	$ 27,689	63,382	$ 112,222	$ 43,895
Net cash used in operating activities									$ 60,073	$ 103,737	$ 36,227
Number of operating segments \| segment									1
Line of Credit Agreement
Organization And Basis Of Presentation [Line Items]
Borrowing capacity	$ 50,000								$ 50,000			$ 50,000

Significant Accounting Policies - Property and Equipment (Details)	12 Months Ended
	Dec. 31, 2019
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 Policies - Right-of-Use Assets and Related Lease Liabilities (Details) - USD ($) $ in Thousands	Jan. 01, 2019	Dec. 31, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right of use assets		$ 27,082
Lease liabilities		$ 33,054
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Lease, Practical Expedients, Package	true
Restatement Adjustment \| Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right of use assets	$ 17,700
Lease liabilities	26,400
Reversal deferred rent credit	$ 8,700

Significant Accounting Policies - Chargebacks and Returns (Details)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Period chargebacks are generally settled	28 days
Period for product return past its expiration or damaged	12 months

Significant Accounting Policies - Advertising (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accounting Policies [Abstract]
Advertising expense	$ 8.0	$ 2.5	$ 0.3

Significant Accounting Policies - Major Customers and Major Suppliers (Details) - Customer Concentration Risk	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Distributor A \| Percentage of Total Revenue
Concentration Risk [Line Items]
Concentration risk, percentage	25.00%	31.00%	29.00%
Distributor A \| Percentage of Accounts Receivable
Concentration Risk [Line Items]
Concentration risk, percentage	23.00%	27.00%	31.00%
Distributor B \| Percentage of Total Revenue
Concentration Risk [Line Items]
Concentration risk, percentage	24.00%	27.00%	26.00%
Distributor B \| Percentage of Accounts Receivable
Concentration Risk [Line Items]
Concentration risk, percentage	19.00%	25.00%	23.00%
Distributor C \| Percentage of Total Revenue
Concentration Risk [Line Items]
Concentration risk, percentage	29.00%	22.00%	22.00%
Distributor C \| Percentage of Accounts Receivable
Concentration Risk [Line Items]
Concentration risk, percentage	33.00%	25.00%	26.00%
Distributor D \| Percentage of Total Revenue
Concentration Risk [Line Items]
Concentration risk, percentage	22.00%	20.00%	23.00%
Distributor D \| Percentage of Accounts Receivable
Concentration Risk [Line Items]
Concentration risk, percentage	25.00%	23.00%	20.00%

Net Loss Per Share (Details) - shares	12 Months Ended
Net Loss Per Share (Details) - shares	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Outstanding dilutive securities not included in diluted loss per share calculation	11,451,046	10,556,253	9,757,861
Stock Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Outstanding dilutive securities not included in diluted loss per share calculation	11,207,931	10,313,138	9,657,259
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	243,115	243,115	100,602

Accounts Receivable, Net - Grant and Other Receivables (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Balance Sheet Related Disclosures [Abstract]
Trade receivables, net	$ 35,074	$ 22,654
Sublease and other receivables	111	164
Total accounts receivables, net	35,185	22,818
Chargeback and product return allowances	$ 1,600	$ 400

Fair-Value Measurements - Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Money-market funds classified as non-current restricted investments	$ 1,154	$ 1,154
Money-market funds classified as short-term investments	57,704	54,637
Fair Value, Measurements, Recurring \| Money Market Funds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Money-market funds classified as non-current restricted investments	1,154	1,154
Money-market funds classified as short-term investments	57,704	54,637
Total	58,858	55,791
Fair Value, Measurements, Recurring \| Level 1 \| Money Market Funds
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Money-market funds classified as non-current restricted investments	1,154	1,154
Money-market funds classified as short-term investments	57,704	54,637
Total	$ 58,858	$ 55,791

Fair-Value Measurements - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Nov. 30, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	$ 3,084	$ 5,861
Unrealized gain (loss) on investments	$ 0	$ 0
Convertible Debt \| Convertible Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest Rate			6.25%

Certain Balance Sheet Accounts - Inventory (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Inventory Disclosure [Abstract]
Raw materials	$ 91	$ 83
Work-in-process	338
Finished goods	718	5
Total inventory	$ 1,147	$ 88

Certain Balance Sheet Accounts - Property and Equipment, Net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Total cost	$ 9,864	$ 8,090
Less accumulated depreciation and amortization	(6,035)	(4,245)
Total property and equipment, net	3,829	3,845
Depreciation and amortization	1,790	962	$ 551
Finance leases
Property, Plant and Equipment [Line Items]
Total cost	5,474	4,034
Laboratory equipment
Property, Plant and Equipment [Line Items]
Total cost	2,844	2,569
Computer equipment
Property, Plant and Equipment [Line Items]
Total cost	921	862
Office equipment and furniture
Property, Plant and Equipment [Line Items]
Total cost	$ 625	$ 625

Certain Balance Sheet Accounts - Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Payables and Accruals [Abstract]
Contract research and development	$ 24,107	$ 12,012
Sales rebates, fees and discounts	10,870	8,075
Consulting and professional fees	3,610	3,669
Employee compensation	3,546	2,714
Clinical trials	1,982	820
Interest payable	1,640	1,677
Other accrued expenses	872	1,219
Total accrued expenses	$ 46,627	$ 30,186

Debt (Details) - USD ($)		1 Months Ended				12 Months Ended
Debt (Details) - USD ($)	May 31, 2018	Aug. 31, 2019	Nov. 30, 2018	May 31, 2018	Oct. 31, 2016	Dec. 31, 2018	Dec. 31, 2019
Debt Instrument [Line Items]
Loss on early extinguishment of debt						$ 12,993,000
CRG Loan
Debt Instrument [Line Items]
Debt issued	$ 45,000,000.0				$ 80,000,000.0
Interest Rate					12.25%
Deferred interest rate percentage					4.00%
Facility fee, as a percent					5.00%
Prepayment fee, as a percent					4.00%
Loss on early extinguishment of debt			$ 13,000,000.0
Convertible Debt \| Convertible Notes
Debt Instrument [Line Items]
Convertible Notes initially issued			$ 210,000,000.0			$ 210,000,000	$ 210,000,000
Interest Rate			6.25%
Line of Credit Agreement
Debt Instrument [Line Items]
Borrowing capacity		$ 50,000,000.0					50,000,000.0
Basis for variable rate		5.50%
Debt termination fee		$ 1,000,000.0
Payment of initial commitment fee		150,000
Additional commitment fees payable each of the first and second anniversaries of the closing date		$ 150,000
Outstanding borrowings							$ 0
Line of Credit Agreement \| Maximum
Debt Instrument [Line Items]
Borrowing option - percentage of eligible accounts receivable		85.00%
Warrants to purchase common stock
Debt Instrument [Line Items]
Total fair value of warrants				$ 1,400,000
Warrants to purchase common stock \| CRG Loan
Debt Instrument [Line Items]
Warrant exercise price (in USD per share)	$ 23.00			$ 23.00
Warrants to purchase common stock \| CRG Loan \| Maximum
Debt Instrument [Line Items]
Shares of common stock right to purchase by warrant (in shares)	200,000			200,000

Convertible Senior Notes - Net Proceeds (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Nov. 30, 2018	Dec. 31, 2018
Debt Instrument [Line Items]
Proceeds from Convertible Debt		$ 210,000
Issuance costs		$ (6,800)
CRG Loan
Debt Instrument [Line Items]
Repayment of previously outstanding loan	$ (146,046)
Convertible Debt \| Convertible Notes
Debt Instrument [Line Items]
Proceeds from Convertible Debt	210,000
Issuance costs	(6,800)
Net proceeds available for corporate use	23,974
Convertible Debt \| Capped Call Transaction
Debt Instrument [Line Items]
Purchase of Capped Call	$ (33,180)

Convertible Senior Notes - Narrative (Details)	1 Months Ended	3 Months Ended	12 Months Ended
Convertible Senior Notes - Narrative (Details)	Nov. 30, 2018 USD ($) D $ / shares	Jun. 30, 2019 D	Dec. 31, 2018 USD ($)	Dec. 31, 2019 USD ($)
Debt Instrument [Line Items]
Proceeds from Convertible Debt			$ 210,000,000
Debt issuance costs			6,800,000
Convertible Debt \| Convertible Notes
Debt Instrument [Line Items]
Interest Rate	6.25%
Conversion rate	0.0520183
Conversion Price \| $ / shares	$ 19.22
Value used in calculation of conversion rate	$ 1,000
Percentage of Stock Price Trigger	150.00%	130.00%
Trading Days \| D	20	20
Consecutive Trading Days \| D	30	30
Measurement Period	5 days
Percent Of Last Product Sale	98.00%
Proceeds from Convertible Debt	$ 210,000,000
Debt issuance costs	6,800,000
Fair value			$ 186,900,000	$ 208,163,000
Convertible Debt \| Capped Call Transaction
Debt Instrument [Line Items]
Purchase of Capped Call	33,180,000
Fair value	$ 33,200,000
Convertible Debt \| Capped Call Transaction \| Minimum
Debt Instrument [Line Items]
Conversion Price \| $ / shares	$ 19.22
Convertible Debt \| Capped Call Transaction \| Maximum
Debt Instrument [Line Items]
Conversion Price \| $ / shares	$ 28.8360

Convertible Senior Notes - Balance of Convertible Notes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Nov. 30, 2018
Debt Instrument [Line Items]
Total Convertible Notes, net	$ 158,213	$ 148,981
Convertible Debt \| Convertible Notes
Debt Instrument [Line Items]
Convertible Notes initially issued	210,000	210,000	$ 210,000
Unamortized discount	(47,660)	(56,156)
Unamortized issuance costs attributable to principal amount	(4,127)	(4,863)
Total Convertible Notes, net	158,213	148,981
Fair value of outstanding Convertible Notes	208,163	186,900
Amount by which the Convertible Notes if-converted value exceeds their principal amount	$ 0	$ 0

Lease Liabilities (Details) $ in Thousands	12 Months Ended
Lease Liabilities (Details) $ in Thousands	Dec. 31, 2019 USD ($) item
Leases [Abstract]
Option to Extend	true
Number of options to extend lease \| item	2
Term of contract	5 years
Classification on the Balance Sheet
Operating lease assets	$ 27,082
Finance lease assets	$ 2,973
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	Property, Plant and Equipment, Net
Total lease assets	$ 30,055
Operating Leases	$ 2,282
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	Operating And Finance Lease Liability Current
Finance Lease	$ 1,222
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	Operating And Finance Lease Liability Current
Operating	$ 30,772
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Operating And Finance Lease Liability Noncurrent
Finance	$ 1,546
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Operating And Finance Lease Liability Noncurrent
Total lease liabilities	$ 35,822
Operating leases	7 years 9 months 18 days
Finance leases	2 years 6 months
Operating leases	12.85%
Finance leases	12.17%
Operating cash flows used for operating leases	$ 6,951
Operating cash flows used for finance leases	337
Financing cash flows used for finance leases	1,139
Lease cost
Operating lease cost	4,604
Amortization	1,340
Interest	337
Short-term lease cost	275
Variable lease cost	2,045
Sublease income	(913)
Total lease cost	$ 7,688

Lease Liabilities - Maturities (Details) $ in Thousands	Dec. 31, 2019 USD ($)
Operating Leases
2020	$ 6,398
2021	6,536
2022	6,678
2023	6,823
2024	6,972
Thereafter	19,590
Total undiscounted lease payments	52,997
Less interest	19,943
Lease liabilities	$ 33,054
Operating Lease, Liability, Statement of Financial Position [Extensible List]	omer:OperatingAndFinanceLeaseLiabilityCurrent omer:OperatingAndFinanceLeaseLiabilityNoncurrent
Finance Lease, Liability, Statement of Financial Position [Extensible List]	omer:OperatingAndFinanceLeaseLiabilityCurrent omer:OperatingAndFinanceLeaseLiabilityNoncurrent
Right of use assets	$ 27,082
Finance Leases
2020	1,434
2021	1,076
2022	490
2023	131
2024	27
Total undiscounted lease payments	3,158
Less interest	390
Lease liabilities	2,768
Additional office and laboratory space
Operating Leases
Right of use assets	10,400
Finance Leases
Lease liabilities	$ 10,400

Commitments and Contingencies (Details) $ in Millions	Dec. 31, 2019 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Contract termination fees	$ 22.7

Shareholders' Equity - Reserved Share of Common Stock (Details)	Dec. 31, 2019 shares
Reserved Common Stock [Line Items]
Total shares reserved	16,848,648
Options granted and outstanding
Reserved Common Stock [Line Items]
Total shares reserved	11,207,931
Options available for future grant
Reserved Common Stock [Line Items]
Total shares reserved	5,397,602
Common stock warrants
Reserved Common Stock [Line Items]
Total shares reserved	243,115

Shareholders' Equity - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended		12 Months Ended
	Dec. 31, 2019	Aug. 31, 2017	Dec. 31, 2019	Dec. 31, 2017
Class of Stock [Line Items]
Shares reserved for issuance	16,900,000		16,900,000
Issuance of stock (in shares)	4,400,000	3,000,000.0
Share price (in USD per share)	$ 13.10	$ 22.75	$ 13.10
Proceeds from issuance of common stock, net	$ 54,200	$ 63,600	$ 54,238	$ 63,657
9.94
Class of Stock [Line Items]
Shares of common stock right to purchase by warrant (in shares)	43,115		43,115
Warrant exercise price (in USD per share)	$ 9.94		$ 9.94
23.00
Class of Stock [Line Items]
Shares of common stock right to purchase by warrant (in shares)	200,000		200,000
Warrant exercise price (in USD per share)	$ 23.00		$ 23.00

Stock-Based Compensation - Narrative (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for issuance		16,900,000
Shares available for future grants (shares)		5,400,000
Stock-based compensation expense		$ 13,785	$ 11,713	$ 12,688
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted (shares)	1,600,000
Exercise price (USD per share)	11.91
Stock options, average vesting period	4 years
Intrinsic value		$ 5,400	$ 11,400	16,400
Unvested options outstanding (shares)		3,000,000.0
Period for recognition		2 years 7 months 6 days
Unrecognized compensation expense		$ 24,200
Stock Options \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Contractual term		10 years
Stock Options \| Nonemployee
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted (shares)		20,000	20,000
Stock-based compensation expense		$ 200	$ 200	$ 500

Stock-Based Compensation - Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 13,785	$ 11,713	$ 12,688
Research and development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	6,095	4,961	5,240
Selling, general and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 7,690	$ 6,752	$ 7,448

Stock-Based Compensation - Fair Value of Employee Option Grant Estimated on Date of Grant (Details) - Equity Option - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Estimated weighted-average fair value (USD per share)	$ 9.93	$ 10.32	$ 8.66
Weighted Average
Weighted-average assumptions
Expected volatility	80.00%	78.00%	74.00%
Expected term, in years	6 years	6 years	6 years
Risk-free interest rate	2.41%	2.68%	2.05%
Expected dividend yield	0.00%	0.00%	0.00%

Stock-Based Compensation - Summary of Stock Option Activity and Related Information (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) $ / shares shares
Options Outstanding
Beginning balance (shares) \| shares	10,313,138
Granted (shares) \| shares	2,098,705
Exercised (shares) \| shares	(799,815)
Forfeited (shares) \| shares	(404,097)
Ending balance (shares) \| shares	11,207,931
Vested and expected to vest (shares) \| shares	10,876,043
Exercisable (shares) \| shares	8,212,177
Weighted-Average Exercise Price per Share
Beginning balance (USD per share) \| $ / shares	$ 11.22
Granted (USD per share) \| $ / shares	14.23
Exercised (USD per share) \| $ / shares	9.50
Forfeited (USD per share) \| $ / shares	16.28
Ending balance (USD per share) \| $ / shares	11.72
Vested and expected to vest (USD per share) \| $ / shares	11.65
Exercisable (USD per share) \| $ / shares	$ 10.87
Weighted- Average Remaining Contractual Life
Balance (in years)	6 years
Vested and expected to vest (in years)	6 years
Exercisable (in years)	5 years 1 month 6 days
Aggregate Intrinsic Value
Balance \| $	$ 31,912
Vested and expected to vest \| $	31,661
Exercisable \| $	$ 29,546

Income Taxes - Components of Income Tax Benefit (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Federal	$ 0	$ 0	$ 0
State	0	0	0
Total current income tax benefit	0	0	0
Federal	0	11,261	0
State	0	1,668	0
Total deferred income tax benefit	0	12,929	0
Income tax benefit	$ 0	$ 12,929	$ 0

Income Taxes - Significant Components of Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Net operating loss carryforwards	$ 126,794	$ 113,928
Research and development tax credits	40,654	35,739
Stock-based compensation	9,959	8,969
Deferred rent		2,037
Lease liability	7,908
Other	14,555	10,413
Total deferred tax assets	199,870	171,086
Deferred tax liabilities:
Equity component of Convertible Notes	(11,082)	(12,706)
Right of use assets	(6,480)
Total deferred tax liabilities	17,562	12,706
Net deferred tax assets before valuation allowance	182,308	158,380
Less valuation allowance	(182,308)	(158,380)
Net deferred tax assets	$ 0	$ 0

Income Taxes - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
Income Taxes - Narrative (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Taxes
Income tax benefit	$ 0	$ 12,929	$ 0
Deferred tax assets, percentage of valuation allowance	100.00%
Increase (decrease) in deferred tax valuation allowance	$ 23,900	26,400
Federal
Income Taxes
Operating Loss Carryforwards	564,300	513,200
State
Income Taxes
Operating Loss Carryforwards	$ 170,500	$ 125,000

Income Taxes - Reconciliation of Federal Statutory Tax Rate (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
U.S. Federal statutory rate on net loss	(21.00%)	(21.00%)	(34.00%)
State tax, net of federal tax benefit	(2.00%)	(2.00%)	(2.00%)
Effects of statutory rate change	0.00%	0.00%	115.00%
Change in valuation allowance	28.00%	19.00%	(60.00%)
Tax credits	(6.00%)	(5.00%)	(11.00%)
Other	1.00%	0.00%	(8.00%)
Effective tax rate	0.00%	(9.00%)	0.00%

401k Retirement Plan - Narrative (Details)	12 Months Ended
401k Retirement Plan - Narrative (Details)	Dec. 31, 2019 USD ($)
Retirement Benefits [Abstract]
Maximum percent of each employee's contributions matched by employer	4.00%
Maximum company match per employee	$ 4,000

Quarterly Information (Unaudited) - Quarterly Unaudited Statements of Operations (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 33,417	$ 29,856	$ 26,753	$ 21,779	$ 22,017	$ 4,608	$ 1,655	$ 1,588	$ 111,805	$ 29,868	$ 64,826
Revenue, Product and Service [Extensible List]	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember	us-gaap:ProductMember
Total costs and expenses	$ 57,121	$ 40,957	$ 36,091	$ 41,018	$ 40,491	$ 40,050	$ 32,272	$ 29,277	$ 175,187	$ 142,090	$ 108,721
Loss from operations	(23,704)	(11,101)	(9,338)	(19,239)	(18,474)	(35,442)	(30,617)	(27,689)	(63,382)	(112,222)	(43,895)
Net loss	$ (29,225)	$ (16,463)	$ (14,453)	$ (24,345)	$ (23,534)	$ (39,472)	$ (33,696)	$ (30,054)	$ (84,486)	$ (126,757)	$ (53,481)
Basic and diluted net loss per share (USD per share)	$ (0.58)	$ (0.33)	$ (0.29)	$ (0.50)	$ (0.48)	$ (0.81)	$ (0.70)	$ (0.62)	$ (1.71)	$ (2.61)	$ (1.17)

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details