(11) Revenue

On January 1, 2018, the Company adopted a new revenue accounting standard, "Revenue from Contracts with Customers" (ASC 606). Upon adoption using the modified retrospective application, the Company recognized a $1.3 million decrease to accumulated deficit, a $0.8 million decrease in deferred revenue and $0.5 million increase in accounts receivable due to the cumulative impact of adopting ASC 606. This impact was driven by the acceleration of revenue using a percentage-of-completion method of accounting under ASC 606 for an open contract that had previously been accounted for using the Contingency Adjusted Performance Model ("CAPM") under previous guidance.

Results for reporting periods beginning after January 1, 2018 are presented under ASC 606 while prior period amounts were not adjusted and continue to be reported in accordance with historic accounting under previous guidance. There was not a material impact to revenues as a result of applying ASC 606 for the three and six month periods ended June 30, 2018, and there have not been significant changes to the Company's business processes, systems or internal controls as a result of adopting the new standard. The Company expects revenue recognition to remain largely unchanged under the new standard.

Revenue Recognition

Revenues are recognized when performance obligations under agreements or contracts are satisfied, in an amount that reflects the consideration the Company expects to be entitled to in exchange for those services.

The Company determines revenue recognition through the following steps:

Identification of the contract, or contracts, with a customer;

Identification of the performance obligations in the contract;

Determination of the transaction price;

Allocation of the transaction price to the performance obligations in the contract; and

Recognition of revenue when, or as, the Company satisfies a performance obligation.

Revenue for the Company has historically been derived from biopharmaceutical product development agreements with collaborative partners for the research and development of therapeutic drug candidates. The terms of the agreements may include nonrefundable signing and licensing fees, funding for research, development and manufacturing, milestone payments and royalties on any product sales derived from collaborations. The Company assesses the multiple obligations typically within product development contracts to determine the distinct performance obligations and how to allocate the arrangement consideration to each distinct performance obligation.

Under product development agreements, revenue is generally recognized using a cost-to-cost measure of progress. Revenue is recognized based on the costs incurred to date as a percentage of the total estimated costs to fulfill the contract. Incurred cost represents work performed, which corresponds with, and thereby best depicts, the transfer of control to the customer. Due to the nature of the work performed in these arrangements, the estimation of cost at completion is complex, subject to many variables, such as expected clinical trial costs, and requires significant judgements. Circumstances can arise that change original estimates of costs or progress toward completion. Any revisions to estimates are reflected in revenue on a cumulative catch-up basis in the period in which the change in circumstances became known.

Revenue for the Company is also derived from manufacturing and research and development arrangements. The Company owns and operates a cGMP manufacturing facility in Fall River, Massachusetts, to produce drug substance for its current and planned early-stage clinical trials. In order to utilize excess capacity, the Company has, from time to time, entered into contract manufacturing and research and development arrangements in which services are provided on a time-and-material basis or at a negotiated fixed-price. Revenue from time-and-material contracts is generally recognized on an output basis as labor hours and/or direct expenses are incurred. Under fixed-price contracts, revenue is generally recognized on an output basis as progress is made toward completion of the performance obligations using surveys of performance completed to date.

Contract Assets and Liabilities

The Company classifies the right to consideration in exchange for products or services transferred to a client as either a receivable or a contract asset. A receivable is a right to consideration that is unconditional as compared to a contract asset which is a right to consideration that is conditional upon factors other than the passage of time. At January 1, 2018 and June 30, 2018, the Company's right to consideration under all contracts was considered unconditional, and as such, there were no recorded contract assets.

The Company’s contract liabilities result from arrangements where the Company has received payment in advance of performance under the contract. These amounts are included as deferred revenue within other long-term liabilities and current portion of long-term liabilities on the condensed consolidated balance sheets. Revenue recognized from contract liabilities as of January 1, 2018 during the three and six months ended June 30, 2018 was $1.0 million and $1.5 million, respectively. Revenue expected to be recognized in the future from contract liabilities as performance obligations are satisfied are not expected to be material.

Product Development and Licensing Revenue

The Company’s primary product development and licensing revenue is associated with a clinical collaboration agreement with BMS entered into in 2014 to evaluate the safety, tolerability and preliminary efficacy of varlilumab and Opdivo®, BMS’s PD-1 immune checkpoint inhibitor, in a Phase 1/2 study. Under this agreement, BMS made an upfront payment to Celldex of $5.0 million and provides funding for 50% of the external costs incurred by the Company in connection with the clinical trial. The Company recorded $1.7 million and $2.6 million in revenue related to this agreement during the three and six months ended June 30, 2018, respectively.

Contract and Grants Revenue

In 2017, the Company entered into fixed-fee manufacturing and research and development arrangements with both the International AIDS Vaccine Initiative (IAVI) and Frontier Biotechnologies, Inc (Frontier). The Company recognized $0.4 million and $2.7 million in revenue under these agreements during the three and six months ended June 30, 2018, respectively, and $2.3 million during both the three and six months ended June 30, 2017.

In 2013, the Company entered into an agreement, as amended, with Rockefeller University pursuant to which the Company performs manufacturing and research and development services for Rockefeller University. The Company recognized $0.6 million and $1.3 million in revenue for labor hours and direct costs incurred related to the Rockefeller University agreement during the three and six months ended June 30, 2018, respectively, and $0.3 million and $1.1 million during the three and six months ended June 30, 2017, respectively.