Revenue	6 Months Ended
Jun. 30, 2019
Revenue
Revenue	(12) Revenue 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 $0.1 million and $0.2 million in revenue related to this agreement during the three and six months ended June 30, 2019, respectively, and $1.7 million and $2.6 million during the three and six months ended June 30, 2018, respectively. Contract and Grants Revenue The Company has entered into agreements with Rockefeller University and Duke University pursuant to which the Company performs manufacturing and research and development services on a time-and-materials basis. The Company recognized $0.4 million and $1.5 million in revenue for labor hours and direct costs incurred under these agreements during the three and six months ended June 30, 2019, respectively, and $0.7 million and $1.4 million during the three and six months ended June 30, 2018, respectively. The Company has entered into fixed-fee manufacturing and research and development arrangements with the International AIDS Vaccine Initiative and Frontier Biotechnologies, Inc. The Company recognized $0.1 million and $0.2 million in revenue under these agreements during the three and six months ended June 30, 2019, respectively, and $0.4 million and $2.7 million during the three and six months ended June 30, 2018, respectively. Contract Assets and Liabilities At December 31, 2018 and June 30, 2019, the Company’s right to consideration under all contracts was considered unconditional, and as such, there were no recorded contract assets. At December 31, 2018 and June 30, 2019, the Company had $1.6 million and $0.5 million in contract liabilities recorded, respectively. Revenue recognized from contract liabilities as of December 31, 2018 during the three and six months ended June 30, 2019 was $0.4 million and $1.2 million, respectively.

(12) Revenue

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 $0.1 million and $0.2 million in revenue related to this agreement during the three and six months ended June 30, 2019, respectively, and $1.7 million and $2.6 million during the three and six months ended June 30, 2018, respectively.

Contract and Grants Revenue

The Company has entered into agreements with Rockefeller University and Duke University pursuant to which the Company performs manufacturing and research and development services on a time-and-materials basis. The Company recognized $0.4 million and $1.5 million in revenue for labor hours and direct costs incurred under these agreements during the three and six months ended June 30, 2019, respectively, and $0.7 million and $1.4 million during the three and six months ended June 30, 2018, respectively.

The Company has entered into fixed-fee manufacturing and research and development arrangements with the International AIDS Vaccine Initiative and Frontier Biotechnologies, Inc. The Company recognized $0.1 million and $0.2 million in revenue under these agreements during the three and six months ended June 30, 2019, respectively, and $0.4 million and $2.7 million during the three and six months ended June 30, 2018, respectively.

Contract Assets and Liabilities

At December 31, 2018 and June 30, 2019, the Company’s right to consideration under all contracts was considered unconditional, and as such, there were no recorded contract assets. At December 31, 2018 and June 30, 2019, the Company had $1.6 million and $0.5 million in contract liabilities recorded, respectively. Revenue recognized from contract liabilities as of December 31, 2018 during the three and six months ended June 30, 2019 was $0.4 million and $1.2 million, respectively.