Collaborative Research, Development and License Agreements	12 Months Ended
Dec. 31, 2021
Research and Development [Abstract]
Collaborative Research, Development and License Agreements	9. Collaborative Research, Development and License Agreements Coalition for Epidemic Preparedness Innovations In September 2020, we entered into a Reservation Agreement for the Provision of Goods (the “Reservation Agreement”) with Coalition for Epidemic Preparedness Innovations (“CEPI”) to make available specified quantities of CpG 1018 adjuvant, for purchases at certain prices, to CEPI and its COVID-19 vaccine development partners. Payments received under the Reservation Agreement are considered an exchange for our CpG 1018 adjuvant which is an output of our ordinary activities. As such, we account for the arrangement under the scope of ASC 606. Payments are recorded as deferred revenue and recognized as revenue in the period when we satisfy our performance obligation to deliver CpG 1018 ordered or when CEPI’s right to place an order expires. Pursuant to the Reservation Agreement, we received $6.3 million from CEPI in September 2020 for production scale-up and a fourth quarter 2020 reservation fee. In October 2020, CEPI terminated the Reservation Agreement and its right to place an order expired. Therefore, we recognized $6.3 million as other revenue in the fourth quarter of 2020. In January 2021, we entered into an agreement (the “CEPI Agreement”) with CEPI for the manufacture and reservation of a specified quantity of CpG 1018 adjuvant (“CpG 1018 Materials”). The CEPI Agreement enables CEPI to direct the supply of CpG 1018 Materials to CEPI partners. CEPI partner(s) would purchase CpG 1018 Materials under separately negotiated agreements. The CEPI Agreement also allows us to sell CpG 1018 Materials to third parties if not purchased by a CEPI partner within a two-year term. In exchange for reserving CpG 1018 Materials and agreeing to sell CpG 1018 Materials to CEPI partner(s) at pre-negotiated prices, CEPI agreed to provide payments in the form of an interest-free, unsecured, forgivable loan (the “Advance Payments”) of up to $99.0 million. We are obligated to repay the Advance Payments, in proportion to quantity sold, if and to the extent we receive payments from sales of CpG 1018 Materials reserved under the CEPI Agreement. If the vaccine programs pursued by CEPI partner(s) are unsuccessful and no alternative use is found for CpG 1018 Materials reserved under the CEPI Agreement, the applicable Advance Payments will be forgiven at the end of the two-year term. In May 2021, we entered into the first Amendment to the CEPI Agreement. This Amendment provided for the manufacture and reservation of an additional specified quantity of CpG 1018 adjuvant. In exchange for reserving an additional specified quantity of CpG 1018 adjuvant, CEPI agreed to provide additional Advance Payments of up to $77.4 million, together with the initial CEPI Agreement, for total Advance Payments of up to $176.4 million. We determined that the accounting of the Advance Payments is under the scope of ASC 606. The Advance Payments are to cover the costs of manufacture and to reserve CpG 1018 Materials, which is an output of our ordinary activities. As such, the Advance Payments are initially classified as long-term deferred revenue in our consolidated balance sheets. We are obligated to repay CEPI, in proportion to quantity sold and within a certain period, upon receipt of payment from CEPI partner(s). Thus, when we deliver CpG 1018 Materials to CEPI partner(s) or when we receive payment from CEPI partner(s), we reclassify the Advanced Payments from long-term deferred revenue to accrued liabilities. We recognize the Advance Payments as revenue when the amount (or a portion thereof) is forgiven by CEPI when (i) the CpG 1018 Materials are not sold through to CEPI partner(s), (ii) there is no alternative use and (iii) the CpG 1018 Materials are destroyed. Through December 31, 2021, we have received Advance Payments totaling approximately $168.5 million pursuant to the CEPI Agreement. As of December 31, 2021, advance payments totaling $5.4 million were included in other long-term liabilities and $128.8 million were recorded as CEPI accrual in our consolidated balance sheets. As of December 31, 2021, we recorded $14.6 million in CEPI receivable which is included in other receivables in our consolidated balance sheets. There were no such balances recorded in our consolidated balance sheets as of December 31, 2020. Zhejiang Clover Biopharmaceuticals, Inc. and Clover Hong Kong Inc. In June 2021, we entered into an agreement with Zhejiang Clover Biopharmaceuticals, Inc. and Clover Hong Kong Inc. (collectively, “Clover”), for the commercial supply of CpG 1018 adjuvant, for use with Clover’s COVID-19 vaccine candidate, SCB-2019 (the “Clover Supply Agreement”). Under the Clover Supply Agreement, Clover has committed to purchase specified quantities of CpG 1018 adjuvant, at pre-negotiated prices pursuant to the CEPI Agreement, for use in Clover’s commercialization of vaccines containing SCB-2019 and CpG 1018 adjuvant (“Clover Product”). The Clover Supply Agreement also provides terms for Clover to order additional quantities of CpG 1018 adjuvant beyond the quantities reserved by CEPI. Pricing for CpG 1018 adjuvant is variable depending on the destination where Clover ultimately sells Clover Product to. Pursuant to the Clover Supply Agreement, our initial invoicing is at the lowest price tier, with a true-up mechanism to issue additional invoice for the difference between the initial invoice price and the higher tiered price, if any. In addition, if the net selling price of such Clover Product exceeds a threshold specified in the Clover Supply Agreement, we are entitled to a royalty calculated as a percentage of the excess portion of such net selling price. For CpG 1018 adjuvant reserved for Clover under the CEPI Agreement, Clover is obligated to pay the purchase price upon the earliest of (i) the true-up exercise, (ii) within a specified period after Clover delivers Clover Product to a customer, or (iii) Clover’s receipt of payment for Clover Product from a customer. For CpG 1018 adjuvant ordered by Clover outside the CEPI Agreement, Clover is obligated to pay a specified percentage of the purchase price, as set forth in a purchase order submitted by Clover, upon our acceptance of such purchase order, and the remainder of the purchase price upon the release of such CpG 1018 adjuvant. We recognize revenue at the lowest price tier upon transfer of control of CpG 1018 adjuvant to Clover. The potential true-up amount and royalties are considered constrained. There is no significant financing component, as the timing between shipment and payment is expected to be within twelve months. Payments received or invoices issued before we transfer control of CpG 1018 adjuvant are recorded as deferred revenue. When we transfer control of CpG 1018 adjuvant that is reserved under the CEPI Agreement, we recognize product revenue and a corresponding contract asset as our right to consideration is contingent on something other than the passage of time, as outlined above. As of December 31, 2021, our contract asset balance of $62.5 million was included in other current assets in our consolidated balance sheets. As of December 31, 2021, we recorded accounts receivable balance of $2.1 million from Clover. As of December 31, 2021, we recognized approximately $191.1 million in deferred revenue for a portion of Clover’s binding commitment to purchase CpG 1018 adjuvant outside the CEPI Agreement. There was no deferred revenue recognized for a portion of Clover’s binding commitment to purchase CpG 1018 adjuvant that was reserved for Clover under the CEPI Agreement. There was no contract asset, accounts receivable or deferred revenue balance at the beginning of the period. For the year ended December 31, 2021, we recognized CpG 1018 product revenue of $72.2 million from Clover. There was no CpG 1018 product revenue from Clover recognized during the year ended December 31, 2020 and 2019. Biological E. Limited In July 2021, we entered into an agreement (the “Bio E Supply Agreement”) with Biological E. Limited (“Bio E”), for the commercial supply of CpG 1018 adjuvant, for use with Bio E’s subunit COVID-19 vaccine candidate, CORBEVAX™. Under the Bio E Supply Agreement, Bio E has committed to purchase specified quantities of CpG 1018 adjuvant, at pre-negotiated prices pursuant to the CEPI Agreement, for use in Bio E’s commercialization of its CORBEVAX vaccine (“Bio E Product”) with specified delivery dates in 2021 and the first quarter of 2022. The Bio E Supply Agreement also provides terms for Bio E to order additional quantities of CpG 1018 adjuvant beyond the quantities reserved by CEPI. Pricing for CpG 1018 adjuvant is variable depending on the destination where Bio E ultimately sells Bio E Product to. Pursuant to the Bio E Supply Agreement, our initial invoicing will be at the lowest price tier, with a true-up mechanism to issue additional invoice for the difference between the initial invoice price and the higher tiered price, if any. In addition, if the net selling price of such Bio E Product exceeds a threshold specified in the Bio E Supply Agreement, we are entitled to a royalty calculated as a percentage of the excess portion of such net selling price. For CpG 1018 adjuvant reserved for Bio E under the CEPI Agreement, Bio E is obligated to pay, in full, the aggregate purchase price, as set forth in a purchase order submitted by Bio E, upon delivery of CpG 1018 adjuvant. For CpG 1018 adjuvant ordered by Bio E outside the CEPI Agreement, Bio E is obligated to pay a specified percentage of the purchase price, as set forth in a purchase order submitted by Bio E, upon our acceptance of such purchase order, and the remainder of the purchase price upon the delivery of such CpG 1018 adjuvant. We recognize revenue at the lowest price tier upon transfer of control of CpG 1018 adjuvant to Bio E. The potential true-up amount and royalties are considered constrained. There is no significant financing component, as the timing between shipment and payment is expected to be within twelve months. Payments received or invoices issued before we transfer control of CpG 1018 adjuvant are recorded as deferred revenue. As of December 31, 2021, we recorded accounts receivable balance of $96.1 million from Bio E. As of December 31, 2021, we recognized approximately $103.3 million in deferred revenue for a portion of Bio E’s binding commitment to purchase CpG 1018 adjuvant outside the CEPI Agreement. There was no deferred revenue recognized for a portion of Bio E’s binding commitment to purchase CpG 1018 adjuvant that was reserved for Bio E under the CEPI Agreement. There was no accounts receivable or deferred revenue balance at the beginning of the period. For the year ended December 31, 2021, we recognized CpG 1018 product revenue of $185.7 million from Bio E. There was no CpG 1018 product revenue from Bio E recognized during the year ended December 31, 2020 and 2019. Medigen Vaccine Biologics In February 2021, we entered into a Supply Agreement (“Medigen Supply Agreement”) with Medigen Vaccine Biologics (“Medigen”) to manufacture and supply specified quantities of CpG 1018 adjuvant for use in the development and commercialization of Medigen’s COVID-19 vaccine for delivery in the first and second quarters of 2021. In August 2021, we entered into a second supply agreement (“Medigen Supply Agreement No. 2”) to manufacture and supply additional specified quantities of CpG 1018 adjuvant for delivery in the third and fourth quarter of 2021. Under Medigen Supply Agreement No. 2, pricing for CpG 1018 adjuvant is variable depending on the destination where Medigen ultimately sells Medigen Product to. Pursuant to the Medigen Supply Agreement No. 2, we invoice Medigen based on the highest-tier price, with a true-up mechanism to issue credit to Medigen for the difference between the initial invoice price and the lower tiered price, if any. We invoice Medigen a specified percentage of the aggregate price of the order upon acceptance of the order and the remaining upon delivery. In addition, we are entitled to a royalty calculated as a percentage of the adjusted net sales. We recognize revenue upon transfer of control of CpG 1018 adjuvant to Medigen at the highest-tiered price. The potential royalties are considered constrained. There is no significant financing component, as the timing between shipment and payment is expected to be within twelve months. Payments received or invoices issued before we transfer control of CpG 1018 adjuvant are recorded as deferred revenue. As of December 31, 2021, we recorded accounts receivable balance of $2.4 million from Medigen. There was no accounts receivable balance at the beginning of the period. For the year ended December 31, 2021 and 2020, we recognized CpG 1018 product revenue from Medigen of $26.7 million and $1.2 million, respectively. There was no CpG 1018 product revenue from Medigen recognized during the year ended December 31, 2019. Valneva SE In April 2020, we entered into a collaboration agreement ("Valneva Collaboration Agreement") with Valneva Scotland Limited (“Valneva”) to provide CpG 1018 adjuvant for use in the development of Valneva’s COVID-19 vaccine candidate ("VLA2001"). The Valneva Collaboration Agreement was amended in July 2020, to provide additional quantities of CpG 1018 adjuvant. In September 2020, we entered into a supply agreement (“Valneva Supply Agreement”) with Valneva to manufacture and supply specified quantities of CpG 1018 adjuvant for use in the commercialization of VLA2001. We concluded that the Valneva Collaboration Agreement and the Valneva Supply Agreement were entered into at or near the same time, with the same customer and were negotiated as a package with a single commercial objective to provide CpG 1018 adjuvant to Valneva. Therefore, the Valneva Collaboration Agreement and the Valneva Supply Agreement should be combined and accounted for as a single arrangement. In October 2021, we and Valneva entered into a letter agreement (the “Valneva Amendment”) modifying certain deliverables of the Valneva Supply Agreement. Specifically, the Valneva Amendment modifies the original Valneva Supply Agreement as follows: (1) cancels certain purchase orders for CpG 1018 adjuvant previously issued under the original Valneva Supply Agreement that had not been fulfilled as of the date of the Valneva Amendment; and (2) provides a future delivery schedule for commercial supply of CpG 1018 adjuvant through 2022. As of the date of the Valneva Amendment, we had received non-refundable advance payments of approximately $55.4 million associated with the cancelled purchase orders. In accordance with revenue recognition guidance in ASC 606, the Valneva Amendment was determined to be a contract modification and will be accounted for prospectively as one agreement with consideration allocated to future performance obligations. We have identified one remaining performance obligation which is the delivery of CpG 1018 adjuvant through 2022. The total amount of consideration allocated to the remaining performance obligation includes approximately $55.4 million of advance payments received as of the date of the Valneva Amendment plus additional future consideration to be received in connection with final delivery of product. As of December 31, 2021, approximately $55.4 million of advance payments remain recorded as deferred revenue and will be recognized as product revenue when we satisfy our remaining performance obligation to deliver CpG 1018 adjuvant under the Valneva Amendment. As of December 31, 2021 and 2020, deferred revenue related to Valneva was $55.4 million and $37.0 million, respectively. For the year ended December 31, 2021 and 2020, we recognized CpG 1018 product revenue of $89.4 million and $2.0 million, respectively. There was no CpG 1018 product revenue from Valneva recognized during the year ended December 31, 2019. Bill & Melinda Gates Foundation Grant Agreement In July 2020, we entered into a grant agreement (the "BMGF Grant Agreement") with Bill & Melinda Gates Foundation (“BMGF”), under which we were awarded a grant of up to $3.4 million to scale up production of our CpG 1018 adjuvant to support the global COVID-19 response and we received $1.2 million of the grant from BMGF which we accounted for as deferred revenue in our consolidated balance sheets as of December 31, 2020. In July 2021, the BMGF Grant Agreement expired. Pursuant to the BMGF Grant Agreement, we were not obligated to return the $1.2 million funding that we spent on grant-related activities. For the year ended December 31, 2021, we recognized $1.2 million as other revenue in our consolidated statements of operations. U.S. Department of Defense In September 2021, we entered into an agreement with the U.S. Department of Defense ("DoD") for the development of a recombinant plague vaccine adjuvanted with CpG 1018 for approximately $22.0 million over two and a half years. Under the agreement, we will conduct a Phase 2 clinical trial combining our CpG 1018 adjuvant with the DoD's rF1V vaccine. We anticipate the Phase 2 trial will commence in 2022. For the year ended December 31, 2021, we recognized revenue of $0.5 million which are included in other revenue in our consolidated statements of operations. Serum Institute of India Pvt. Ltd. In June 2017, we entered into an agreement to provide Serum Institute of India Pvt. Ltd. (“SIIPL”) with technical support. In consideration, SIIPL agreed to pay us at an agreed upon hourly rate for services and reimburse certain out-of-pocket expenses. In addition, we have rights to commercialization of certain potential products manufactured at the SIIPL facility. For the years ended December 31, 2021, 2020 and 2019, we recognized collaboration revenue of $0.4 million, $0.9 million and $0.1 million, respectively which are included in other revenue in our consolidated statements of operations.

Collaborative Research, Development and License Agreements

12 Months Ended

Dec. 31, 2021

Collaborative Research, Development and License Agreements

Coalition for Epidemic Preparedness Innovations

In September 2020, we entered into a Reservation Agreement for the Provision of Goods (the “Reservation Agreement”) with Coalition for Epidemic Preparedness Innovations (“CEPI”) to make available specified quantities of CpG 1018 adjuvant, for purchases at certain prices, to CEPI and its COVID-19 vaccine development partners. Payments received under the Reservation Agreement are considered an exchange for our CpG 1018 adjuvant which is an output of our ordinary activities. As such, we account for the arrangement under the scope of ASC 606. Payments are recorded as deferred revenue and recognized as revenue in the period when we satisfy our performance obligation to deliver CpG 1018 ordered or when CEPI’s right to place an order expires. Pursuant to the Reservation Agreement, we received $6.3 million from CEPI in September 2020 for production scale-up and a fourth quarter 2020 reservation fee. In October 2020, CEPI terminated the Reservation Agreement and its right to place an order expired. Therefore, we recognized $6.3 million as other revenue in the fourth quarter of 2020.

In January 2021, we entered into an agreement (the “CEPI Agreement”) with CEPI for the manufacture and reservation of a specified quantity of CpG 1018 adjuvant (“CpG 1018 Materials”). The CEPI Agreement enables CEPI to direct the supply of CpG 1018 Materials to CEPI partners. CEPI partner(s) would purchase CpG 1018 Materials under separately negotiated agreements. The CEPI Agreement also allows us to sell CpG 1018 Materials to third parties if not purchased by a CEPI partner within a two-year term.

In exchange for reserving CpG 1018 Materials and agreeing to sell CpG 1018 Materials to CEPI partner(s) at pre-negotiated prices, CEPI agreed to provide payments in the form of an interest-free, unsecured, forgivable loan (the “Advance Payments”) of up to $99.0 million. We are obligated to repay the Advance Payments, in proportion to quantity sold, if and to the extent we receive payments from sales of CpG 1018 Materials reserved under the CEPI Agreement. If the vaccine programs pursued by CEPI partner(s) are unsuccessful and no alternative use is found for CpG 1018 Materials reserved under the CEPI Agreement, the applicable Advance Payments will be forgiven at the end of the two-year term.

In May 2021, we entered into the first Amendment to the CEPI Agreement. This Amendment provided for the manufacture and reservation of an additional specified quantity of CpG 1018 adjuvant. In exchange for reserving an additional specified quantity of CpG 1018 adjuvant, CEPI agreed to provide additional Advance Payments of up to $77.4 million, together with the initial CEPI Agreement, for total Advance Payments of up to $176.4 million.

We determined that the accounting of the Advance Payments is under the scope of ASC 606. The Advance Payments are to cover the costs of manufacture and to reserve CpG 1018 Materials, which is an output of our ordinary activities. As such, the Advance Payments are initially classified as long-term deferred revenue in our consolidated balance sheets. We are obligated to repay CEPI, in proportion to quantity sold and within a certain period, upon receipt of payment from CEPI partner(s). Thus, when we deliver CpG 1018 Materials to CEPI partner(s) or when we receive payment from CEPI partner(s), we reclassify the Advanced Payments from long-term deferred revenue to accrued liabilities. We recognize the Advance Payments as revenue when the amount (or a portion thereof) is forgiven by CEPI when (i) the CpG 1018 Materials are not sold through to CEPI partner(s), (ii) there is no alternative use and (iii) the CpG 1018 Materials are destroyed.

Through December 31, 2021, we have received Advance Payments totaling approximately $168.5 million pursuant to the CEPI Agreement. As of December 31, 2021, advance payments totaling $5.4 million were included in other long-term liabilities and $128.8 million were recorded as CEPI accrual in our consolidated balance sheets. As of December 31, 2021, we recorded $14.6 million in CEPI receivable which is included in other receivables in our consolidated balance sheets. There were no such balances recorded in our consolidated balance sheets as of December 31, 2020.

Zhejiang Clover Biopharmaceuticals, Inc. and Clover Hong Kong Inc.

In June 2021, we entered into an agreement with Zhejiang Clover Biopharmaceuticals, Inc. and Clover Hong Kong Inc. (collectively, “Clover”), for the commercial supply of CpG 1018 adjuvant, for use with Clover’s COVID-19 vaccine candidate, SCB-2019 (the “Clover Supply Agreement”). Under the Clover Supply Agreement, Clover has committed to purchase specified quantities of CpG 1018 adjuvant, at pre-negotiated prices pursuant to the CEPI Agreement, for use in Clover’s commercialization of vaccines containing SCB-2019 and CpG 1018 adjuvant (“Clover Product”). The Clover Supply Agreement also provides terms for Clover to order additional quantities of CpG 1018 adjuvant beyond the quantities reserved by CEPI.

Pricing for CpG 1018 adjuvant is variable depending on the destination where Clover ultimately sells Clover Product to. Pursuant to the Clover Supply Agreement, our initial invoicing is at the lowest price tier, with a true-up mechanism to issue additional invoice for the difference between the initial invoice price and the higher tiered price, if any. In addition, if the net selling price of such Clover Product exceeds a threshold specified in the Clover Supply Agreement, we are entitled to a royalty calculated as a percentage of the excess portion of such net selling price.

For CpG 1018 adjuvant reserved for Clover under the CEPI Agreement, Clover is obligated to pay the purchase price upon the earliest of (i) the true-up exercise, (ii) within a specified period after Clover delivers Clover Product to a customer, or (iii) Clover’s receipt of payment for Clover Product from a customer. For CpG 1018 adjuvant ordered by Clover outside the CEPI Agreement, Clover is obligated to pay a specified percentage of the purchase price, as set forth in a purchase order submitted by Clover, upon our acceptance of such purchase order, and the remainder of the purchase price upon the release of such CpG 1018 adjuvant.

We recognize revenue at the lowest price tier upon transfer of control of CpG 1018 adjuvant to Clover. The potential true-up amount and royalties are considered constrained. There is no significant financing component, as the timing between shipment and payment is expected to be within twelve months. Payments received or invoices issued before we transfer control of CpG 1018 adjuvant are recorded as deferred revenue. When we transfer control of CpG 1018 adjuvant that is reserved under the CEPI Agreement, we recognize product revenue and a corresponding contract asset as our right to consideration is contingent on something other than the passage of time, as outlined above.

As of December 31, 2021, our contract asset balance of $62.5 million was included in other current assets in our consolidated balance sheets. As of December 31, 2021, we recorded accounts receivable balance of $2.1 million from Clover. As of December 31, 2021, we recognized approximately $191.1 million in deferred revenue for a portion of Clover’s binding commitment to purchase CpG 1018 adjuvant outside the CEPI Agreement. There was no deferred revenue recognized for a portion of Clover’s binding commitment to purchase CpG 1018 adjuvant that was reserved for Clover under the CEPI Agreement. There was no contract asset, accounts receivable or deferred revenue balance at the beginning of the period.

For the year ended December 31, 2021, we recognized CpG 1018 product revenue of $72.2 million from Clover. There was no CpG 1018 product revenue from Clover recognized during the year ended December 31, 2020 and 2019.

Biological E. Limited

In July 2021, we entered into an agreement (the “Bio E Supply Agreement”) with Biological E. Limited (“Bio E”), for the commercial supply of CpG 1018 adjuvant, for use with Bio E’s subunit COVID-19 vaccine candidate, CORBEVAX™. Under the Bio E Supply Agreement, Bio E has committed to purchase specified quantities of CpG 1018 adjuvant, at pre-negotiated prices pursuant to the CEPI Agreement, for use in Bio E’s commercialization of its CORBEVAX vaccine (“Bio E Product”) with specified delivery dates in 2021 and the first quarter of 2022. The Bio E Supply Agreement also provides terms for Bio E to order additional quantities of CpG 1018 adjuvant beyond the quantities reserved by CEPI.

Pricing for CpG 1018 adjuvant is variable depending on the destination where Bio E ultimately sells Bio E Product to. Pursuant to the Bio E Supply Agreement, our initial invoicing will be at the lowest price tier, with a true-up mechanism to issue additional invoice for the difference between the initial invoice price and the higher tiered price, if any. In addition, if the net selling price of such Bio E Product exceeds a threshold specified in the Bio E Supply Agreement, we are entitled to a royalty calculated as a percentage of the excess portion of such net selling price.

For CpG 1018 adjuvant reserved for Bio E under the CEPI Agreement, Bio E is obligated to pay, in full, the aggregate purchase price, as set forth in a purchase order submitted by Bio E, upon delivery of CpG 1018 adjuvant. For CpG 1018 adjuvant ordered by Bio E outside the CEPI Agreement, Bio E is obligated to pay a specified percentage of the purchase price, as set forth in a purchase order submitted by Bio E, upon our acceptance of such purchase order, and the remainder of the purchase price upon the delivery of such CpG 1018 adjuvant.

We recognize revenue at the lowest price tier upon transfer of control of CpG 1018 adjuvant to Bio E. The potential true-up amount and royalties are considered constrained. There is no significant financing component, as the timing between shipment and payment is expected to be within twelve months. Payments received or invoices issued before we transfer control of CpG 1018 adjuvant are recorded as deferred revenue.

As of December 31, 2021, we recorded accounts receivable balance of $96.1 million from Bio E. As of December 31, 2021, we recognized approximately $103.3 million in deferred revenue for a portion of Bio E’s binding commitment to purchase CpG 1018 adjuvant outside the CEPI Agreement. There was no deferred revenue recognized for a portion of Bio E’s binding commitment to purchase CpG 1018 adjuvant that was reserved for Bio E under the CEPI Agreement. There was no accounts receivable or deferred revenue balance at the beginning of the period.

For the year ended December 31, 2021, we recognized CpG 1018 product revenue of $185.7 million from Bio E. There was no CpG 1018 product revenue from Bio E recognized during the year ended December 31, 2020 and 2019.

Medigen Vaccine Biologics

In February 2021, we entered into a Supply Agreement (“Medigen Supply Agreement”) with Medigen Vaccine Biologics (“Medigen”) to manufacture and supply specified quantities of CpG 1018 adjuvant for use in the development and commercialization of Medigen’s COVID-19 vaccine for delivery in the first and second quarters of 2021.

In August 2021, we entered into a second supply agreement (“Medigen Supply Agreement No. 2”) to manufacture and supply additional specified quantities of CpG 1018 adjuvant for delivery in the third and fourth quarter of 2021.

Under Medigen Supply Agreement No. 2, pricing for CpG 1018 adjuvant is variable depending on the destination where Medigen ultimately sells Medigen Product to. Pursuant to the Medigen Supply Agreement No. 2, we invoice Medigen based on the highest-tier price, with a true-up mechanism to issue credit to Medigen for the difference between the initial invoice price and the lower tiered price, if any. We invoice Medigen a specified percentage of the aggregate price of the order upon acceptance of the order and the remaining upon delivery. In addition, we are entitled to a royalty calculated as a percentage of the adjusted net sales.

We recognize revenue upon transfer of control of CpG 1018 adjuvant to Medigen at the highest-tiered price. The potential royalties are considered constrained. There is no significant financing component, as the timing between shipment and payment is expected to be within twelve months. Payments received or invoices issued before we transfer control of CpG 1018 adjuvant are recorded as deferred revenue.

As of December 31, 2021, we recorded accounts receivable balance of $2.4 million from Medigen. There was no accounts receivable balance at the beginning of the period. For the year ended December 31, 2021 and 2020, we recognized CpG 1018 product revenue from Medigen of $26.7 million and $1.2 million, respectively. There was no CpG 1018 product revenue from Medigen recognized during the year ended December 31, 2019.

Valneva SE

In April 2020, we entered into a collaboration agreement ("Valneva Collaboration Agreement") with Valneva Scotland Limited (“Valneva”) to provide CpG 1018 adjuvant for use in the development of Valneva’s COVID-19 vaccine candidate ("VLA2001"). The Valneva Collaboration Agreement was amended in July 2020, to provide additional quantities of CpG 1018 adjuvant. In September 2020, we entered into a supply agreement (“Valneva Supply Agreement”) with Valneva to manufacture and supply specified quantities of CpG 1018 adjuvant for use in the commercialization of VLA2001.

We concluded that the Valneva Collaboration Agreement and the Valneva Supply Agreement were entered into at or near the same time, with the same customer and were negotiated as a package with a single commercial objective to provide CpG 1018 adjuvant to Valneva. Therefore, the Valneva Collaboration Agreement and the Valneva Supply Agreement should be combined and accounted for as a single arrangement.

In October 2021, we and Valneva entered into a letter agreement (the “Valneva Amendment”) modifying certain deliverables of the Valneva Supply Agreement. Specifically, the Valneva Amendment modifies the original Valneva Supply Agreement as follows: (1) cancels certain purchase orders for CpG 1018 adjuvant previously issued under the original Valneva Supply Agreement that had not been fulfilled as of the date of the Valneva Amendment; and (2) provides a future delivery schedule for commercial supply of CpG 1018 adjuvant through 2022. As of the date of the Valneva Amendment, we had received non-refundable advance payments of approximately $55.4 million associated with the cancelled purchase orders.

In accordance with revenue recognition guidance in ASC 606, the Valneva Amendment was determined to be a contract modification and will be accounted for prospectively as one agreement with consideration allocated to future performance obligations. We have identified one remaining performance obligation which is the delivery of CpG 1018 adjuvant through 2022. The total amount of consideration allocated to the remaining performance obligation includes approximately $55.4 million of advance payments received as of the date of the Valneva Amendment plus additional future consideration to be received in connection with final delivery of product. As of December 31, 2021, approximately $55.4 million of advance payments remain recorded as deferred revenue and will be recognized as product revenue when we satisfy our remaining performance obligation to deliver CpG 1018 adjuvant under the Valneva Amendment.

As of December 31, 2021 and 2020, deferred revenue related to Valneva was $55.4 million and $37.0 million, respectively. For the year ended December 31, 2021 and 2020, we recognized CpG 1018 product revenue of $89.4 million and $2.0 million, respectively. There was no CpG 1018 product revenue from Valneva recognized during the year ended December 31, 2019.

Bill & Melinda Gates Foundation Grant Agreement

In July 2020, we entered into a grant agreement (the "BMGF Grant Agreement") with Bill & Melinda Gates Foundation (“BMGF”), under which we were awarded a grant of up to $3.4 million to scale up production of our CpG 1018 adjuvant to support the global COVID-19 response and we received $1.2 million of the grant from BMGF which we accounted for as deferred revenue in our consolidated balance sheets as of December 31, 2020.

In July 2021, the BMGF Grant Agreement expired. Pursuant to the BMGF Grant Agreement, we were not obligated to return the $1.2 million funding that we spent on grant-related activities. For the year ended December 31, 2021, we recognized $1.2 million as other revenue in our consolidated statements of operations.

U.S. Department of Defense

In September 2021, we entered into an agreement with the U.S. Department of Defense ("DoD") for the development of a recombinant plague vaccine adjuvanted with CpG 1018 for approximately $22.0 million over two and a half years. Under the agreement, we will conduct a Phase 2 clinical trial combining our CpG 1018 adjuvant with the DoD's rF1V vaccine. We anticipate the Phase 2 trial will commence in 2022. For the year ended December 31, 2021, we recognized revenue of $0.5 million which are included in other revenue in our consolidated statements of operations.

Serum Institute of India Pvt. Ltd.

In June 2017, we entered into an agreement to provide Serum Institute of India Pvt. Ltd. (“SIIPL”) with technical support. In consideration, SIIPL agreed to pay us at an agreed upon hourly rate for services and reimburse certain out-of-pocket expenses. In addition, we have rights to commercialization of certain potential products manufactured at the SIIPL facility. For the years ended December 31, 2021, 2020 and 2019, we recognized collaboration revenue of $0.4 million, $0.9 million and $0.1 million, respectively which are included in other revenue in our consolidated statements of operations.