4 Collaboration arrangements and concentration of credit risk

The Company generates all its collaboration and license revenues from its Collaboration and License Agreement with BMS, its Co-Development Agreement for AMT-060 and its Glybera Commercialization Agreement with Chiesi Farmaceutici S.p.A. ("Chiesi").

As of June 2015 onwards, BMS is considered a related party given its equity investment in the Company. Chiesi was considered a related party given its equity investment in the Company up to December 31, 2015.

Services to the Company's two collaboration partners are rendered by its Dutch operating entity. Total collaboration and license revenue generated from these partners are as follows:

	Years ended December 31,
	2016		2015		2014
	in thousands
Bristol Myers Squibb	$	16,959	$	4,677	$	—
Chiesi Farmaceutici S.p.A		8,139		5,901		6,141

Total	$	25,098	$	10,578	$	6,141

Amounts owed from these partners in relation to the collaboration are as follows:

	December 31,
	2016		2015
	in thousands
Bristol Myers Squibb	$	5,500	$	1,009
Chiesi Farmaceutici S.p.A		3,680		3,120

Total	$	9,180	$	4,129

BMS collaboration

In May 2015, the Company closed a Collaboration and License Agreement with BMS (the "BMS Agreement"), that provides exclusive access to the Company's gene therapy technology platform for multiple targets in cardiovascular (and other) diseases. The collaboration included the Company's proprietary gene therapy program for congestive heart failure which aims to restore the heart's ability to synthesize S100A1, a calcium sensor and master regulator of heart function, and thereby improve clinical outcomes for patients with reduced ejection fraction. Beyond cardiovascular diseases, the agreement also included the potential for a target exclusive collaboration in other disease areas. In total, the companies may collaborate on ten targets, including S100A1.

The Company is leading the discovery, non-clinical, analytical and process development effort and is responsible for manufacturing of clinical and commercial supplies using the Company's vector technologies and industrial, proprietary insect-cell based manufacturing platform, while BMS leads the clinical development and regulatory activities across all programs and reimburses the Company for all research and development efforts. BMS will be solely responsible for commercialization of all products from the collaboration.

The Company evaluated the BMS Agreement and determined that it is a revenue arrangement with multiple elements. The Company's substantive deliverables under the collaboration agreement include an exclusive license to its technology in the field of cardiovascular disease, research and development services for specific targets chosen by BMS and general development of the Company's proprietary vector technology, participation in the Joint Steering Committee, and clinical and commercial manufacturing. The Company concluded that the collaboration agreement consists of three units of accounting, including (i) technology (license and target selections), know-how and manufacturing in the field of gene therapy and development and active contribution to the development through the Joint Steering Committee participations, (ii) provision of employees, goods and services for research activities for specific targets and (iii) clinical and commercial manufacturing. The Company determined that the license does not have stand-alone value to BMS without the Company's know-how and manufacturing technology through the participation of the Joint Steering Committee and accordingly, they were combined into one unit of accounting.

License revenue—BMS

As of the Effective Date (May 21, 2015) of the BMS Agreement, the Company recorded deferred revenue of $60.1 million, which was equal to the up-front consideration payment of $50.0 million, plus the fair value of the derivative financial instruments at the Execution date ($10.1 million) (see note 3, "Fair value measurement"). On July 31, 2015, BMS selected the second, third and fourth collaboration targets, triggering a $15.0 million target designation payment to the Company. The Company is entitled to $16.5 million in aggregate of target designation payments upon selection of the fifth through tenth collaboration target. The Company will also be eligible to receive research, development and regulatory milestone payments of up to $254.0 million for the first target and up to $217.0 million for the other selected targets if and when achieved. The Company determined that the contingent payments under the BMS Agreement relating to research, development and regulatory milestones do not constitute substantive milestone and will not be accounted for under the milestone method of revenues recognition. The events leading to these payments solely depend on BMS' performance. Accordingly, any revenue from these contingent payments would be allocated to the first unit of accounting noted above and recognized over the expected performance period.

License revenue is recognized over an expected performance period of 19 years on a straight-line basis commencing on the Effective Date. The expected performance period is reviewed quarterly and adjusted to account for changes, if any, in the Company´s estimated performance period. The estimated performance period did not change in 2016.

The Company recognized $3.9 million license revenue for the year ended December 31, 2016 (December 31, 2015: $2.4 million; December 31, 2014: $0.0 million).

Additionally, the Company is eligible to receive net sales-based milestone payments and tiered high single to low double-digit royalties on product sales. These revenues will be recognized when earned. The royalty term is determined on a licensed-product-by-licensed-product and country-by-country basis and begins on the first commercial sale of a licensed product in a country and ends on the expiration of the last to expire of specified patents or regulatory exclusivity covering such licensed product in such country or, with a customary royalty reduction, ten years after such first commercial sale if there is no such exclusivity.

Collaboration revenue—BMS

The Company provides target-specific research and development services to BMS. Collaboration revenue related to these contracted services, is recognized when earned.

The Company generated $13.0 million collaboration revenue for the year ended December 31, 2016 (December 31, 2015: $2.3 million; December 31, 2014: $0.0 million).

Manufacturing revenue—BMS

The parties entered into a contract for the Company to supply gene therapy products during the clinical and commercial phase to BMS. Revenues from product sales will be recognized when earned. So far the Company did not supply any product to BMS.

Chiesi collaboration

The Company evaluated the collaboration agreement with Chiesi and determined that it is a revenue arrangement with multiple elements. The Company's substantive deliverables under the collaboration agreement include an exclusive license to its technology in the field of cardiovascular disease, research and development services, and commercial manufacturing. The Company concluded that the collaboration agreement consists of three units of accounting, including (i) co-development and active contribution to the collaboration by providing technology access and know-how in the field of gene therapy, (ii) provision of employees, goods and services for research and development activities and (iii) commercial manufacturing.

License revenue—Chiesi

In 2013, the Company entered into an agreement with Chiesi, a family-owned Italian pharmaceutical company for the co-development and commercialization of the AMT-060 program and the commercialization of Glybera. The Company has retained full rights in the United States, Canada and Japan under this agreement. Upon closing of the agreements on June 30, 2013, the Company received €17.0 million ($22.1 million) in non-refundable up-front payments. The Company determined that the up-front payments received from Chiesi related to a single unit of accounting. The up-front payments are amortized on a straight-line basis and presented as license revenues over a period from July 2013 through September 2032, the date of expiration of the last intellectual property protection related to the Company's manufacturing process at such date.

The Company recognized $1.0 million license revenue for the year ended December 31, 2016 (December 31, 2015: $1.0 million; December 31, 2014: $1.2 million).

Collaboration revenue—Chiesi

Chiesi reimburses the Company for 50% of the agreed research and development efforts related to AMT-060, which is presented as collaboration revenue. Once regulatory approval has been obtained, Chiesi will distribute AMT-060 and the Company is entitled to receive a fixed mid double digit royalty as a percentage of Chiesi sales. The Company estimates that the amount it would retain, net of manufacturing costs, third-party royalties and related amounts, will be between 25% and 35% of the revenues from sales realized by Chiesi, varying by country of sale.

The Company generated $7.2 million collaboration revenue for the year ended December 31, 2016 (December 31, 2015: $4.9 million; December 31, 2014: $5.0 million) from the co-development of AMT-060.

Manufacturing revenue—Chiesi

The parties entered into a contract for the Company to supply Glybera to Chiesi. Revenues from product sales, presented as collaboration revenue, will be recognized when earned. In the year ended December 31, 2016, the Company recognized no revenue from product sales to Chiesi (December 31, 2015: $0.3 million; December 31, 2014: nil).