Summary of Significant Accounting Policies	3 Months Ended
Mar. 31, 2019
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Use of Estimates The condensed financial statements have been prepared in accordance with GAAP. The preparation of financial statements in conformity with GAAP requires the Company to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of product sales and expense during the reporting period. Although these estimates are based on the Company’s knowledge of current events and anticipated actions it may undertake in the future, actual results may ultimately materially differ from these estimates and assumptions. Segment Reporting Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision-maker in making decisions regarding resource allocation and assessing performance. The Company views its operations and manages its business in one operating segment. Concentrations of Credit Risk Financial instruments that potentially subject the Company to significant concentrations of credit risk consist primarily of cash, cash equivalents and short-term investments. The Company maintains deposits in federally insured financial institutions in excess of federally insured limits. The Company has not experienced any losses in such accounts and believes it is not exposed to significant risk on its cash balances due to the financial position of the depository institution in which those deposits are held. Additionally, the Company established guidelines regarding approved investments and maturities of investments, which are designed to maintain safety and liquidity. Cash, Cash Equivalents and Restricted Cash Cash and cash equivalents consist of cash and highly liquid investments with original maturities of three months or less at the date of purchase. The carrying amounts approximate fair value due to the short maturities of these instruments. Cash and cash equivalents include cash in readily available checking, savings and money market accounts. The Company’s restricted cash consists of cash maintained in separate deposit accounts to secure a letter of credit issued by a bank to the landlord under a lease agreement for the Company’s corporate headquarters. Short-term Investments The Company carries short-term investments classified as available-for-sale debt securities at fair value as determined by prices for identical or similar securities at the balance sheet date. Short-term investments consist of both Level 1 and Level 2 financial instruments in the fair value hierarchy (see Note 6 – Fair Value). Realized gains or losses of available-for-sale securities are determined using the specific identification method and net realized gains and losses are included in interest income. The Company periodically reviews available-for-sale securities for other-than temporary declines in fair value below the cost basis, and whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. The Company records unrealized gains and losses on available-for-sale debt securities as a component of other comprehensive loss within the condensed statements of comprehensive loss and as a separate component of stockholders’ equity on the condensed balance sheets. The Company does not hold equity securities in its investment portfolio. Fair Value of Financial Instruments The Company’s financial instruments include cash, cash equivalents, short-term investments, prepaid expenses and other assets, accounts payable, accrued expenses, accrued compensation and long-term debt. The carrying value of the Company’s cash and cash equivalents, short-term investments, prepaid expenses and other current assets, other long-term assets, accounts payable, accrued expenses, and accrued compensation approximate fair value due to the short-term nature of these items. Based on Level 3 inputs and the borrowing rates currently available for loans with similar terms, the Company believes the fair value of long-term debt approximates its carrying value. Accounts Receivable, net Accounts receivable are recorded net of customer allowances for chargebacks, distributor fees and any allowance for doubtful accounts. The Company estimates the allowance for doubtful accounts based on existing contractual payment terms, actual payment patterns of its customers and individual customer circumstances. To date, the Company has determined that an allowance for doubtful accounts is not required. Property and Equipment Property and equipment generally consist of manufacturing equipment, office furniture and equipment, computers, and scientific equipment and are recorded at cost and depreciated using the straight-line method over the estimated useful lives of the assets (generally two to ten years). Leasehold improvements are stated at cost and are depreciated on a straight-line basis over the lesser of the remaining term of the related lease or the estimated useful lives of the assets. Repairs and maintenance costs are charged to expense as incurred. Impairment of Long-Lived Assets The Company assesses the value of its long-lived assets, which consist of property and equipment, for impairment on an annual basis and whenever events or changes in circumstances and the undiscounted cash flows generated by those assets indicate that the carrying amount of such assets may not be recoverable. While the Company’s current and historical operating losses and negative cash flows are indicators of impairment, the Company believes that future cash flows to be received support the carrying value of its long-lived assets. The Company had no impairments or disposals of long-lived assets during the three months ended March 31, 2019 and 2018. Right-of-Use Assets and Lease Liabilities The Company has operating leases for its facility and certain equipment and finance leases for certain computer equipment. Effective January 1, 2019, the Company determines if an arrangement is or contains a lease at the commencement date. Operating leases are included in Right-of-use (ROU) assets, Leases, current, and Leases, net of current on the condensed balance sheets. Finance leases are included in Property and equipment, Leases, current, and Leases, net of current on the condensed balance sheets. The Company elected not to recognize short-term leases (one year or less) on the balance sheet. ROU assets and operating lease liabilities are recognized based on the present value of future minimum lease payments over the lease term at the commencement date. When the implicit rate of the lease is not provided or cannot be determined, the Company uses a collateralized incremental borrowing rate based on the information available at the commencement date, including lease term, in determining the present value of future payments. The Company considers payments for common area maintenance, real estate taxes and management fees to be variable non-lease components, which are expensed as incurred. Lease terms may include options to extend or terminate the lease when it is reasonably certain the Company will exercise that option. Lease expense for minimum lease payments is recognized on a straight-line basis over the lease term. Clinical Trial Expense Accruals As part of the process of preparing the Company’s financial statements, the Company is required to estimate expenses resulting from the Company’s obligations under contracts with vendors, clinical research organizations and consultants and under clinical site agreements in connection with conducting clinical trials. The financial terms of these contracts are subject to negotiations, which vary from contract to contract and may result in payment flows that do not match the periods over which materials or services are provided under such contracts. The Company’s objective is to reflect the appropriate clinical trial expenses in its financial statements by recording those expenses in the period in which services are performed and efforts are expended. The Company accounts for these expenses according to the progress of the trial as measured by patient progression and the timing of various aspects of the trial. The Company determines accrual estimates through financial models taking into account discussion with applicable personnel and outside service providers as to the progress or state of its trials. During the course of a clinical trial, the Company adjusts its clinical expense if actual results differ from its estimates. Revenue Recognition To recognize revenue the Company performs the following five steps: (i) identify the contract(s) 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. The Company only applies the five-step model to arrangements that meet the definition of a contract with a customer under ASC 606 and when it is probable the Company will collect the consideration exchanged for the goods or services transferred to the customer. At contract inception, the Company assesses the goods or services promised within each contract and determines those that are performance obligations, and then it assesses whether each promised good or service is distinct. The Company recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when the performance obligation is satisfied. OTIPRIO is sold to a limited number of specialty wholesale distributors. The Company recognizes revenue when its customers obtain control of OTIPRIO, typically upon delivery by the Company to these distributors. The Company has determined the delivery of OTIPRIO to its customers constitutes a single performance obligation and no other performance obligations are present. The Company’s customer contracts have standard payment terms. The Company does not offer prompt pay discounts or financing on sales and has not identified any credit risk issues. Hospitals, ambulatory surgery centers and physician offices order OTIPRIO from the Company’s distributors and are the end users of OTIPRIO. The Company permits product returns from the distributors only if the product is damaged or is shipped or ordered in error. Product returns based on expiry are not permitted. To date, product returns have been immaterial. Sales commissions and other incremental costs of obtaining customer contracts are expensed as incurred as the amortization periods would be less than one year or the amount is immaterial. Transaction Price and Reserves for Variable Consideration Revenue from product sales are recorded at the net sales price (transaction price), which includes estimates of variable consideration for which reserves are established. Components of variable consideration include trade discounts and allowances, government chargebacks, discounts and rebates and other fee for service amounts that are detailed within customer contracts relating to the sale of OTIPRIO. These reserves, as detailed below, are based on the amounts earned or accrued on our sales. Variable consideration is estimated using the most likely method, which is the single most likely outcome under the Company’s contracts and takes into consideration contractual fees, historical chargeback activity and historical Medicaid rebates. Overall, these reserves reflect the Company’s best estimates of the amount of consideration to which the Company is entitled based on the terms of the respective underlying contracts. The amount of variable consideration included in the transaction price may be constrained and is included in the net sales price only to the extent that it is probable a significant reversal in the amount of the cumulative revenue recognized under the contract will not occur in a future period. The Company’s analyses also contemplate application of the constraint in accordance with the guidance, under which the Company determined a material reversal of revenue would not occur in a future period. Reserves are established for these discounts and allowances upon delivery of OTIPRIO by the distributor and are classified as: (i) an allowance against accounts receivable if the amount is payable to the distributor or (ii) an accrued liability if the amount is payable to a party other than the distributor. Allowances against accounts receivable relate to chargebacks and distributor fees and accruals relate primarily to government rebates. Actual amounts of consideration ultimately received may differ from the Company’s estimates. If actual results in the future vary from original estimates, the Company will adjust these estimates, which would affect net product revenue and earnings in the period such variances become known. Trade Discounts and Allowances. The Company’s customers are specialty wholesale distributors with whom the Company has contracted to pay a fee based on a percentage of wholesale acquisition cost for sales order management, data, and distribution services. The Company determined such services received to date are not distinct from the sale of products to customers and, therefore, these payments have been recorded as a reduction of revenue within the statement of operations. This fee for service is recorded as an allowance against accounts receivable at the time of sale based on the contracted percentage. Chargebacks. The Company estimates allowances against accounts receivable for chargebacks related to agreements with group purchasing organizations and federal contracts. Under these agreements, the Company credits distributors a chargeback amount which represents the difference between the wholesale acquisition cost and the discounted price at which eligible purchasers purchased from the distributors. At the time of sale, estimated chargebacks are recorded based on historical chargeback activity, the projected payer mix, patient population industry data and the identification of entities purchasing OTIPRIO that are eligible for discounted pricing. Government Rebates. The Company estimates a rebate liability in connection with a Medicaid Drug Rebate Agreement with the Centers for Medicare & Medicaid Services, which provides a rebate to participating states based on covered purchases of OTIPRIO. At the time of sale, estimated Medicaid rebates are recorded based on historical government rebate activity, the projected payer mix and Medicaid patient population industry data. Concentration of Major Customers The Company sells OTIPRIO to specialty wholesale distributor customers. The Company’s sales to its three largest customers in the first quarter of 2019 accounted for approximately 37%, 32% and 26%, respectively, of the Company’s revenues. The Company’s sales to its three largest customers in the first quarter of 2018 accounted for approximately 43%, 38% and 18%, respectively, of the Company’s revenues. Collaborative Arrangements The Company has entered into co-promotion agreements that fall under the scope of ASC Topic 808, Collaborative Arrangements (ASC 808). The terms of these agreements include (i) annual non-refundable non-creditable payments to the Company and reimbursement to the Company for a proportion of product support expenses as agreed upon by both parties and (ii) payments by the Company for profit sharing arising from our partners’ promotional activities. Payments to the Company are recognized as a reduction of our selling, general and administrative expenses in the statements of operations. Profit-sharing payments by the Company to our partners are recognized as selling, general and administrative expenses. Research and Development Research and development expenses include the costs associated with the Company’s research and development activities, including salaries, benefits, stock-based compensation expense and occupancy costs. Also included in research and development expenses are third-party costs incurred in conjunction with contract manufacturing for the Company’s research and development programs and clinical trials, including the cost of clinical trial drug supply, costs incurred by contract research organizations and regulatory expenses. Research and development costs are expensed as incurred. Selling, General and Administrative Selling, general and administrative expenses include the costs associated with the Company’s executive, administrative, finance and human resource functions including salaries, benefits, stock-based compensation expense and occupancy costs. Other selling, general and administrative expenses include costs associated with prosecuting and maintaining the Company’s patent portfolio, corporate legal expenses, costs required for public company activities and infrastructure necessary for the general conduct of the Company’s business. The Company’s selling, general and administrative expenses also include OTIPRIO product support expenses, and profit-sharing fees payable to the Company’s partners, which are reduced by payments received from our partners under the Company’s co-promotion agreements. Stock-Based Compensation The Company accounts for stock-based compensation expense related to stock options and employee stock purchase plan (ESPP) rights by estimating the fair value on the date of grant using the Black-Scholes-Merton option pricing model. Forfeitures are recognized as incurred. For awards subject to time-based vesting conditions, stock-based compensation expense is recognized using the straight-line method. For performance-based awards to employees, (i) the fair value of the award is determined on the grant date, (ii) we assess the probability of the individual performance milestones under the award being achieved and (iii) the fair value of the shares subject to the milestone is expensed over the implicit service period commencing once management believes the performance criteria is probable of being met. Income Taxes The accounting guidance for uncertainty in income taxes prescribes a recognition threshold and measurement attribute criteria for the financial statement recognition and measurement of tax positions taken or expected to be taken in a tax return. For those benefits to be recognized, a tax position must be more likely than not to be sustained upon examination by taxing authorities based on the technical merits of the position. The Company uses the liability method of accounting for income taxes. Under this method, deferred tax assets and liabilities are determined based on the difference between the financial reporting and the tax reporting basis of assets and liabilities and are measured using the enacted tax rates and laws that are expected to be in effect when the differences are expected to reverse. The Company provides a valuation allowance against net deferred tax assets unless, based upon the available evidence, it is more likely than not that the deferred tax assets will be realized. When the Company establishes or reduces the valuation allowance against its deferred tax assets, its provision for income taxes will increase or decrease, respectively, in the period such determination is made. Comprehensive Loss Comprehensive loss is defined as the change in equity during a period from transactions and other events and/or circumstances from non-owner sources. Net Loss Per Share Basic net loss per common share is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of common shares outstanding during the period, without consideration for potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss attributable to common stockholders by the weighted-average number of common shares and potentially dilutive securities outstanding for the period determined using the treasury-stock and if-converted methods. For purposes of the diluted net loss per share calculation, potentially dilutive securities are excluded from the calculation of diluted net loss per share because their effect would be anti-dilutive and therefore, basic and diluted net loss per share were the same for all periods presented. As of March 31, 2019 and 2018, potentially dilutive securities excluded from the calculation of diluted net loss per share consist of outstanding options to purchase 7,346,935 and 5,427,390 shares of the Company’s common stock, respectively. Recent Accounting Pronouncements Not Yet Adopted In June 2016, the FASB issued Accounting Standards Update (ASU) No. 2016-13, Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (ASU 2016-13). ASU 2016-13 introduces the current expected credit loss (CECL) model, which will require an entity to measure credit losses for certain financial instruments and financial assets. ASU 2016-13 will also apply to receivables arising from revenue transactions such as accounts receivable. At each reporting period, the Company will be required to recognize an allowance that reflects the entity’s current estimate of credit losses expected to be incurred on outstanding trade receivables. ASU 2016-13 is effective for the Company beginning January 1, 2020. The Company does not expect the adoption of ASU 2016-13 to have a material effect on its financial position, results of operations or cash flows. Recently Adopted Effective January 1, 2019, as required, the Company adopted ASU No. 2018-02, Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income (ASU 2018-02). ASU 2018-02 provides the option to reclassify stranded tax effects within accumulated other comprehensive income to retained earnings in each period in which the effect of the change in the U.S. federal corporate income tax rate in the Tax Reform (or portion thereof) is recorded. The adoption of ASU No. 2018-02 did not have a material impact on the Company's financial position, results of operations or cash flows due to the presence of a full valuation allowance. Effective January 1, 2019, as required, the Company adopted ASU No. 2018-07, Compensation – Stock Compensation (Topic 718) – Improvements to Nonemployee Share-Based Payment Accounting (ASU 2018-07). The amendments in ASU 2018-07 expand the scope of the standard to include share-based payment transactions for acquiring goods and services from nonemployees. The adoption of ASU 2018-07 did not have a material impact on its financial statements or disclosures. Effective January 1, 2019, as required by ASU No. 2016-02, Lease (ASU 2016-02), the Company adopted ASC 842, Leases (ASC 842), using a modified retrospective method as of the adoption date. Consequently, financial information will not be updated, and the disclosures required under ASU 2016-02 will not be provided for dates and periods prior to January 1, 2019. ASC 842 supersedes nearly all previously existing lease guidance under GAAP and requires lessees to recognize leases on the balance sheet and disclose key information about leasing arrangements. ASC 842 establishes an ROU model that requires a lessee to recognize a ROU asset and lease liability on the balance sheet for all leases with a term longer than 12 months. ASU 2016-02 provides a number of optional practical expedients and accounting policy elections. The Company elected the package of practical expedients requiring no reassessment of whether any expired or existing contracts are or contain leases, the lease classification of any expired or existing leases, or initial direct costs for any existing leases. The adoption of ASC 842 had a material effect on the Company’s condensed balance sheets; however, it did not have a material effect on its condensed statements of operations, comprehensive loss and cash flows. Upon adoption of ASC 842, the Company recognized (i) right-of-use assets of $16.7 million, net of $3.0 million of deferred rent, and (ii) lease liabilities of $19.7 million. (see Note 7 - Leases).

Summary of Significant Accounting Policies

3 Months Ended

Mar. 31, 2019

Summary of Significant Accounting Policies

2. Summary of Significant Accounting Policies

Use of Estimates

The condensed financial statements have been prepared in accordance with GAAP. The preparation of financial statements in conformity with GAAP requires the Company to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of product sales and expense during the reporting period. Although these estimates are based on the Company’s knowledge of current events and anticipated actions it may undertake in the future, actual results may ultimately materially differ from these estimates and assumptions.

Segment Reporting

Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision-maker in making decisions regarding resource allocation and assessing performance. The Company views its operations and manages its business in one operating segment.

Concentrations of Credit Risk

Financial instruments that potentially subject the Company to significant concentrations of credit risk consist primarily of cash, cash equivalents and short-term investments. The Company maintains deposits in federally insured financial institutions in excess of federally insured limits. The Company has not experienced any losses in such accounts and believes it is not exposed to significant risk on its cash balances due to the financial position of the depository institution in which those deposits are held. Additionally, the Company established guidelines regarding approved investments and maturities of investments, which are designed to maintain safety and liquidity.

Cash, Cash Equivalents and Restricted Cash

Cash and cash equivalents consist of cash and highly liquid investments with original maturities of three months or less at the date of purchase. The carrying amounts approximate fair value due to the short maturities of these instruments. Cash and cash equivalents include cash in readily available checking, savings and money market accounts.

The Company’s restricted cash consists of cash maintained in separate deposit accounts to secure a letter of credit issued by a bank to the landlord under a lease agreement for the Company’s corporate headquarters.

Short-term Investments

The Company carries short-term investments classified as available-for-sale debt securities at fair value as determined by prices for identical or similar securities at the balance sheet date. Short-term investments consist of both Level 1 and Level 2 financial instruments in the fair value hierarchy (see Note 6 – Fair Value).

Realized gains or losses of available-for-sale securities are determined using the specific identification method and net realized gains and losses are included in interest income. The Company periodically reviews available-for-sale securities for other-than temporary declines in fair value below the cost basis, and whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. The Company records unrealized gains and losses on available-for-sale debt securities as a component of other comprehensive loss within the condensed statements of comprehensive loss and as a separate component of stockholders’ equity on the condensed balance sheets. The Company does not hold equity securities in its investment portfolio.

Fair Value of Financial Instruments

The Company’s financial instruments include cash, cash equivalents, short-term investments, prepaid expenses and other assets, accounts payable, accrued expenses, accrued compensation and long-term debt. The carrying value of the Company’s cash and cash equivalents, short-term investments, prepaid expenses and other current assets, other long-term assets, accounts payable, accrued expenses, and accrued compensation approximate fair value due to the short-term nature of these items. Based on Level 3 inputs and the borrowing rates currently available for loans with similar terms, the Company believes the fair value of long-term debt approximates its carrying value.

Accounts Receivable, net

Accounts receivable are recorded net of customer allowances for chargebacks, distributor fees and any allowance for doubtful accounts. The Company estimates the allowance for doubtful accounts based on existing contractual payment terms, actual payment patterns of its customers and individual customer circumstances. To date, the Company has determined that an allowance for doubtful accounts is not required.

Property and Equipment

Property and equipment generally consist of manufacturing equipment, office furniture and equipment, computers, and scientific equipment and are recorded at cost and depreciated using the straight-line method over the estimated useful lives of the assets (generally two to ten years). Leasehold improvements are stated at cost and are depreciated on a straight-line basis over the lesser of the remaining term of the related lease or the estimated useful lives of the assets. Repairs and maintenance costs are charged to expense as incurred.

Impairment of Long-Lived Assets

The Company assesses the value of its long-lived assets, which consist of property and equipment, for impairment on an annual basis and whenever events or changes in circumstances and the undiscounted cash flows generated by those assets indicate that the carrying amount of such assets may not be recoverable. While the Company’s current and historical operating losses and negative cash flows are indicators of impairment, the Company believes that future cash flows to be received support the carrying value of its long-lived assets. The Company had no impairments or disposals of long-lived assets during the three months ended March 31, 2019 and 2018.

Right-of-Use Assets and Lease Liabilities

The Company has operating leases for its facility and certain equipment and finance leases for certain computer equipment. Effective January 1, 2019, the Company determines if an arrangement is or contains a lease at the commencement date. Operating leases are included in Right-of-use (ROU) assets, Leases, current, and Leases, net of current on the condensed balance sheets. Finance leases are included in Property and equipment, Leases, current, and Leases, net of current on the condensed balance sheets. The Company elected not to recognize short-term leases (one year or less) on the balance sheet.

ROU assets and operating lease liabilities are recognized based on the present value of future minimum lease payments over the lease term at the commencement date. When the implicit rate of the lease is not provided or cannot be determined, the Company uses a collateralized incremental borrowing rate based on the information available at the commencement date, including lease term, in determining the present value of future payments. The Company considers payments for common area maintenance, real estate taxes and management fees to be variable non-lease components, which are expensed as incurred. Lease terms may include options to extend or terminate the lease when it is reasonably certain the Company will exercise that option. Lease expense for minimum lease payments is recognized on a straight-line basis over the lease term.

Clinical Trial Expense Accruals

As part of the process of preparing the Company’s financial statements, the Company is required to estimate expenses resulting from the Company’s obligations under contracts with vendors, clinical research organizations and consultants and under clinical site agreements in connection with conducting clinical trials. The financial terms of these contracts are subject to negotiations, which vary from contract to contract and may result in payment flows that do not match the periods over which materials or services are provided under such contracts.

The Company’s objective is to reflect the appropriate clinical trial expenses in its financial statements by recording those expenses in the period in which services are performed and efforts are expended. The Company accounts for these expenses according to the progress of the trial as measured by patient progression and the timing of various aspects of the trial. The Company determines accrual estimates through financial models taking into account discussion with applicable personnel and outside service providers as to the progress or state of its trials. During the course of a clinical trial, the Company adjusts its clinical expense if actual results differ from its estimates.

Revenue Recognition

To recognize revenue the Company performs the following five steps: (i) identify the contract(s) 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. The Company only applies the five-step model to arrangements that meet the definition of a contract with a customer under ASC 606 and when it is probable the Company will collect the consideration exchanged for the goods or services transferred to the customer. At contract inception, the Company assesses the goods or services promised within each contract and determines those that are performance obligations, and then it assesses whether each promised good or service is distinct. The Company recognizes as revenue the amount of the transaction price that is allocated to the respective performance obligation when the performance obligation is satisfied.

OTIPRIO is sold to a limited number of specialty wholesale distributors. The Company recognizes revenue when its customers obtain control of OTIPRIO, typically upon delivery by the Company to these distributors. The Company has determined the delivery of OTIPRIO to its customers constitutes a single performance obligation and no other performance obligations are present. The Company’s customer contracts have standard payment terms. The Company does not offer prompt pay discounts or financing on sales and has not identified any credit risk issues.

Hospitals, ambulatory surgery centers and physician offices order OTIPRIO from the Company’s distributors and are the end users of OTIPRIO. The Company permits product returns from the distributors only if the product is damaged or is shipped or ordered in error. Product returns based on expiry are not permitted. To date, product returns have been immaterial.

Sales commissions and other incremental costs of obtaining customer contracts are expensed as incurred as the amortization periods would be less than one year or the amount is immaterial.

Transaction Price and Reserves for Variable Consideration

Revenue from product sales are recorded at the net sales price (transaction price), which includes estimates of variable consideration for which reserves are established. Components of variable consideration include trade discounts and allowances, government chargebacks, discounts and rebates and other fee for service amounts that are detailed within customer contracts relating to the sale of OTIPRIO. These reserves, as detailed below, are based on the amounts earned or accrued on our sales. Variable consideration is estimated using the most likely method, which is the single most likely outcome under the Company’s contracts and takes into consideration contractual fees, historical chargeback activity and historical Medicaid rebates. Overall, these reserves reflect the Company’s best estimates of the amount of consideration to which the Company is entitled based on the terms of the respective underlying contracts.

The amount of variable consideration included in the transaction price may be constrained and is included in the net sales price only to the extent that it is probable a significant reversal in the amount of the cumulative revenue recognized under the contract will not occur in a future period. The Company’s analyses also contemplate application of the constraint in accordance with the guidance, under which the Company determined a material reversal of revenue would not occur in a future period. Reserves are established for these discounts and allowances upon delivery of OTIPRIO by the distributor and are classified as: (i) an allowance against accounts receivable if the amount is payable to the distributor or (ii) an accrued liability if the amount is payable to a party other than the distributor. Allowances against accounts receivable relate to chargebacks and distributor fees and accruals relate primarily to government rebates. Actual amounts of consideration ultimately received may differ from the Company’s estimates. If actual results in the future vary from original estimates, the Company will adjust these estimates, which would affect net product revenue and earnings in the period such variances become known.

Trade Discounts and Allowances. The Company’s customers are specialty wholesale distributors with whom the Company has contracted to pay a fee based on a percentage of wholesale acquisition cost for sales order management, data, and distribution services. The Company determined such services received to date are not distinct from the sale of products to customers and, therefore, these payments have been recorded as a reduction of revenue within the statement of operations. This fee for service is recorded as an allowance against accounts receivable at the time of sale based on the contracted percentage.

Chargebacks. The Company estimates allowances against accounts receivable for chargebacks related to agreements with group purchasing organizations and federal contracts. Under these agreements, the Company credits distributors a chargeback amount which represents the difference between the wholesale acquisition cost and the discounted price at which eligible purchasers purchased from the distributors. At the time of sale, estimated chargebacks are recorded based on historical chargeback activity, the projected payer mix, patient population industry data and the identification of entities purchasing OTIPRIO that are eligible for discounted pricing.

Government Rebates. The Company estimates a rebate liability in connection with a Medicaid Drug Rebate Agreement with the Centers for Medicare & Medicaid Services, which provides a rebate to participating states based on covered purchases of OTIPRIO. At the time of sale, estimated Medicaid rebates are recorded based on historical government rebate activity, the projected payer mix and Medicaid patient population industry data.

Concentration of Major Customers

The Company sells OTIPRIO to specialty wholesale distributor customers. The Company’s sales to its three largest customers in the first quarter of 2019 accounted for approximately 37%, 32% and 26%, respectively, of the Company’s revenues. The Company’s sales to its three largest customers in the first quarter of 2018 accounted for approximately 43%, 38% and 18%, respectively, of the Company’s revenues.

Collaborative Arrangements

The Company has entered into co-promotion agreements that fall under the scope of ASC Topic 808, Collaborative Arrangements (ASC 808). The terms of these agreements include (i) annual non-refundable non-creditable payments to the Company and reimbursement to the Company for a proportion of product support expenses as agreed upon by both parties and (ii) payments by the Company for profit sharing arising from our partners’ promotional activities. Payments to the Company are recognized as a reduction of our selling, general and administrative expenses in the statements of operations. Profit-sharing payments by the Company to our partners are recognized as selling, general and administrative expenses.

Research and Development

Research and development expenses include the costs associated with the Company’s research and development activities, including salaries, benefits, stock-based compensation expense and occupancy costs. Also included in research and development expenses are third-party costs incurred in conjunction with contract manufacturing for the Company’s research and development programs and clinical trials, including the cost of clinical trial drug supply, costs incurred by contract research organizations and regulatory expenses. Research and development costs are expensed as incurred.

Selling, General and Administrative

Selling, general and administrative expenses include the costs associated with the Company’s executive, administrative, finance and human resource functions including salaries, benefits, stock-based compensation expense and occupancy costs. Other selling, general and administrative expenses include costs associated with prosecuting and maintaining the Company’s patent portfolio, corporate legal expenses, costs required for public company activities and infrastructure necessary for the general conduct of the Company’s business. The Company’s selling, general and administrative expenses also include OTIPRIO product support expenses, and profit-sharing fees payable to the Company’s partners, which are reduced by payments received from our partners under the Company’s co-promotion agreements.

Stock-Based Compensation

The Company accounts for stock-based compensation expense related to stock options and employee stock purchase plan (ESPP) rights by estimating the fair value on the date of grant using the Black-Scholes-Merton option pricing model. Forfeitures are recognized as incurred. For awards subject to time-based vesting conditions, stock-based compensation expense is recognized using the straight-line method. For performance-based awards to employees, (i) the fair value of the award is determined on the grant date, (ii) we assess the probability of the individual performance milestones under the award being achieved and (iii) the fair value of the shares subject to the milestone is expensed over the implicit service period commencing once management believes the performance criteria is probable of being met.

Income Taxes

The accounting guidance for uncertainty in income taxes prescribes a recognition threshold and measurement attribute criteria for the financial statement recognition and measurement of tax positions taken or expected to be taken in a tax return. For those benefits to be recognized, a tax position must be more likely than not to be sustained upon examination by taxing authorities based on the technical merits of the position.

The Company uses the liability method of accounting for income taxes. Under this method, deferred tax assets and liabilities are determined based on the difference between the financial reporting and the tax reporting basis of assets and liabilities and are measured using the enacted tax rates and laws that are expected to be in effect when the differences are expected to reverse. The Company provides a valuation allowance against net deferred tax assets unless, based upon the available evidence, it is more likely than not that the deferred tax assets will be realized. When the Company establishes or reduces the valuation allowance against its deferred tax assets, its provision for income taxes will increase or decrease, respectively, in the period such determination is made.

Comprehensive Loss

Comprehensive loss is defined as the change in equity during a period from transactions and other events and/or circumstances from non-owner sources.

Net Loss Per Share

Basic net loss per common share is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of common shares outstanding during the period, without consideration for potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss attributable to common stockholders by the weighted-average number of common shares and potentially dilutive securities outstanding for the period determined using the treasury-stock and if-converted methods. For purposes of the diluted net loss per share calculation, potentially dilutive securities are excluded from the calculation of diluted net loss per share because their effect would be anti-dilutive and therefore, basic and diluted net loss per share were the same for all periods presented.

As of March 31, 2019 and 2018, potentially dilutive securities excluded from the calculation of diluted net loss per share consist of outstanding options to purchase 7,346,935 and 5,427,390 shares of the Company’s common stock, respectively.

Recent Accounting Pronouncements

Not Yet Adopted

In June 2016, the FASB issued Accounting Standards Update (ASU) No. 2016-13, Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments (ASU 2016-13). ASU 2016-13 introduces the current expected credit loss (CECL) model, which will require an entity to measure credit losses for certain financial instruments and financial assets. ASU 2016-13 will also apply to receivables arising from revenue transactions such as accounts receivable. At each reporting period, the Company will be required to recognize an allowance that reflects the entity’s current estimate of credit losses expected to be incurred on outstanding trade receivables. ASU 2016-13 is effective for the Company beginning January 1, 2020. The Company does not expect the adoption of ASU 2016-13 to have a material effect on its financial position, results of operations or cash flows.

Recently Adopted

Effective January 1, 2019, as required, the Company adopted ASU No. 2018-02, Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income (ASU 2018-02). ASU 2018-02 provides the option to reclassify stranded tax effects within accumulated other comprehensive income to retained earnings in each period in which the effect of the change in the U.S. federal corporate income tax rate in the Tax Reform (or portion thereof) is recorded. The adoption of ASU No. 2018-02 did not have a material impact on the Company's financial position, results of operations or cash flows due to the presence of a full valuation allowance.

Effective January 1, 2019, as required, the Company adopted ASU No. 2018-07, Compensation – Stock Compensation (Topic 718) – Improvements to Nonemployee Share-Based Payment Accounting (ASU 2018-07). The amendments in ASU 2018-07 expand the scope of the standard to include share-based payment transactions for acquiring goods and services from nonemployees. The adoption of ASU 2018-07 did not have a material impact on its financial statements or disclosures.

Effective January 1, 2019, as required by ASU No. 2016-02, Lease (ASU 2016-02), the Company adopted ASC 842, Leases (ASC 842), using a modified retrospective method as of the adoption date. Consequently, financial information will not be updated, and the disclosures required under ASU 2016-02 will not be provided for dates and periods prior to January 1, 2019. ASC 842 supersedes nearly all previously existing lease guidance under GAAP and requires lessees to recognize leases on the balance sheet and disclose key information about leasing arrangements.

ASC 842 establishes an ROU model that requires a lessee to recognize a ROU asset and lease liability on the balance sheet for all leases with a term longer than 12 months. ASU 2016-02 provides a number of optional practical expedients and accounting policy elections. The Company elected the package of practical expedients requiring no reassessment of whether any expired or existing contracts are or contain leases, the lease classification of any expired or existing leases, or initial direct costs for any existing leases.

The adoption of ASC 842 had a material effect on the Company’s condensed balance sheets; however, it did not have a material effect on its condensed statements of operations, comprehensive loss and cash flows. Upon adoption of ASC 842, the Company recognized (i) right-of-use assets of $16.7 million, net of $3.0 million of deferred rent, and (ii) lease liabilities of $19.7 million. (see Note 7 - Leases).