Summary of Significant Accounting Policies	3 Months Ended
Summary of Significant Accounting Policies	Mar. 31, 2021
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	During the three months ended March 31, 2021, the Company adopted the following significant accounting policies in addition to those previously disclosed in the Company’s Annual Report on Form 10-K for the year ended December 31, 2020. Inventory The company outsources the manufacturing of MARGENZA. Prior to FDA approval of MARGENZA in December 2020, the cost of materials and expenses associated with the manufacturing of MARGENZA were recorded as research and development expense. Subsequent to regulatory approval, the Company began capitalizing MARGENZA inventory costs. The Company values its inventories at the lower of cost and estimated net realizable value. The Company determines the cost of its inventories, which includes amounts related to materials and third-party contract manufacturing costs, on a first-in, first-out basis. The Company performs an assessment of the recoverability of capitalized inventory during each reporting period, and it writes down any excess and obsolete inventories to their estimated realizable value in the period in which the impairment is first identified. Such write downs, should they occur, are recorded within the cost of sales in the statement of operations. As of March 31, 2021, the Company’s inventory balance consisted primarily of raw materials purchased and work in progress manufactured after the FDA approval of MARGENZA. Product Revenue, Net The Company entered into a limited number of arrangements with specialty distributors in the United States to distribute MARGENZA. These arrangements are considered to be contracts with customers and are in the scope of Accounting Standards Codification Topic 606, Revenue from Contracts with Customers (ASC 606). The Company has written contracts with each of its customers that have a single performance obligation - to deliver products upon receipt of a customer order - and these obligations are satisfied when delivery occurs and the customer receives the product. The specialty distributors subsequently resell the Company’s product to healthcare providers. Product revenue is recorded net of applicable reserves for variable consideration, including discounts and other allowances. Shipping and handling costs for product shipments occur prior to the customer obtaining control of the goods and are recorded in cost of sales. For the three months ended March 31, 2021, the shipping costs incurred were immaterial. Reserves for Variable Consideration Revenue from product sales is recorded at the net sales price, which includes estimates of variable consideration. Components of variable consideration typically include discounts, product returns, provider chargebacks and discounts and government rebates. Variable consideration is estimated following the expected value method in accordance with ASC 606 and includes such factors as current contractual and statutory requirements, specific known market events and trends, industry data, and forecasted customer buying and payment patterns. The amount of variable consideration that is included in the transaction price may be constrained and is included in the net sales price only to the extent that it is probable that a significant reversal in the amount of the cumulative revenue recognized under the contract will not occur in a future period. Estimates of the variable consideration were not deemed constrained during the three months ended March 31, 2021. Customer Discounts and Service Fees The Company may provide customers with discounts which are explicitly stated in the contracts. These discounts are recorded as a reduction of revenue in the period the related product revenue is recognized. In addition, these contracts may include written service arrangements whereby the Company pays fees to customers who provide services such as sales order management, data, contract administration and distribution services, at rates which we believe to be consistent with fair market value. The Company has determined such services received to date are not distinct from the Company’s sale of products to its customers and, therefore, these payments have been recorded as a reduction of revenue within the statement of operations. Product Returns Consistent with industry practice, the Company offers the specialty distributors product return rights pursuant to written contracts and/or Company returned goods policies. The Company estimates the amount of its product sales that may be returned by its customers and records an estimated liability and a reduction of revenue in the period the related product revenue is recognized. The Company currently estimates product returns using industry benchmarking as well as other information available, such as visibility into the inventory remaining in the distribution channel, since the Company does not have its own returns experience. The Company's estimates of product returns may be adjusted in the future based on actual returns experience, known or expected changes in the marketplace, or other factors. Provider Chargebacks and Discounts Chargebacks for fees and discounts to healthcare providers represent the estimated obligations resulting from contractual commitments to sell products to qualified healthcare providers at prices lower than the list prices charged to customers who directly purchase the product from the Company. In such cases, customers charge the Company for the difference between what they pay for the product and the ultimate selling price to the qualified healthcare providers. The reserve for chargebacks is established in the same period that the related revenue is recognized, resulting in a reduction of product revenue. Chargeback amounts are generally determined at the time of resale to the qualified healthcare provider by customers, and the Company generally issues credits for such amounts within a few weeks of the customer’s notification to the Company of the resale. Chargebacks consist of credits the Company expects to issue for units that remain in the distribution channel at each reporting period end that the Company expects will be sold to qualified healthcare providers and chargebacks that customers have claimed, but for which the Company has not yet issued a credit. Government Rebates The Company is subject to discount and/or rebate obligations under state Medicaid programs, Medicare and contractual agreements with and statutory obligations to certain Federal and State entities. These reserves are recorded in the same period the related revenue is recognized, resulting in a reduction of product revenue. The Company’s liability for these rebates consists of invoices received for claims from prior quarters that have not been paid or for which an invoice has not yet been received, estimates of claims for the current quarter, and estimates of future claims that will be made for product that has been recognized as revenue, but which remains in the distribution channel at the end of each reporting period. Customer discounts and service fees are recorded as reductions of accounts receivable on the consolidated balance sheets. Allowance for product returns, provider chargebacks and government and other rebates are recorded as a component of accrued expenses and other current liabilities on the consolidated balance sheets. Cost of product sales Cost of product sales relates to sales of MARGENZA. These costs include material, manufacturing and shipping costs, as well as royalties payable on net sales of MARGENZA. All product costs incurred prior to FDA approval of MARGENZA in December 2020 were expensed as research and development expense. The Company expects cost of product sales to continue to be positively impacted as the Company sells through inventory that was expensed prior to FDA approval of MARGENZA in December 2020. The Company is currently unable to estimate how long it will be until it begins selling product manufactured post FDA approval. Recent Accounting Pronouncements In December 2019, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes (ASU 2019-12). ASU 2019-12 is part of the FASB’s overall simplification initiative and seeks to simplify the accounting for income taxes by updating certain guidance and removing certain exceptions. The updated guidance is effective for fiscal years beginning after December 15, 2020 and interim periods within those fiscal years. The adoption of this standard as of January 1, 2021 had no impact on the Company's consolidated financial statements and related disclosures. The Company has evaluated all other ASUs issued through the date the consolidated financials were issued and believes that the adoption of these ASUs will not have a material impact on the Company's consolidated financial statements.