Under Topic 606, the Company recognizes revenues when its customer obtains control of promised goods or services, in an amount that reflects the consideration the Company expects to receive in exchange for those goods or services. The Company recognizes revenues following the five-step model prescribed under Topic 606: (i) identify contract(s) with a customer; (ii) identify the performance obligation(s) in the contract(s); (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligation(s) in the contract(s); and (v) recognize revenues when (or as) the Company satisfies the performance obligation(s).

During the three months ended March 31, 2019 and 2018, the Company recorded manufacturing and royalty revenues as follows:

	Three Months Ended March 31, 2019
(In thousands)	Manufacturing Revenue		Royalty Revenue		Total
INVEGA SUSTENNA/XEPLION & INVEGA TRINZA/TREVICTA	$	—	$	53,298	$	53,298
RISPERDAL CONSTA		17,921		4,385		22,306
AMPYRA/FAMPYRA		5,680		6,506		12,186
Other		7,346		13,779		21,125
	$	30,947	$	77,968	$	108,915

	Three Months Ended March 31, 2018
(In thousands)	Manufacturing Revenue		Royalty Revenue		Total
INVEGA SUSTENNA/XEPLION & INVEGA TRINZA/TREVICTA	$	—	$	46,086	$	46,086
AMPYRA/FAMPYRA		13,563		14,696		28,259
RISPERDAL CONSTA		17,792		4,912		22,704
Other		6,236		11,316		17,552
	$	37,591	$	77,010	$	114,601

The Company’s product sales, net consist of sales of VIVITROL and ARISTADA (together with ARISTADA INITIO) in the U.S. primarily to wholesalers, specialty distributors and pharmacies. Product sales, net are recognized when the customer obtains control of the product, which is when the product has been received by the customer.

During the three months ended March 31, 2019 and 2018, the Company recorded product sales, net, as follows:

	Three Months Ended March 31,
(In thousands)	2019		2018
VIVITROL	$	69,183	$	62,682
ARISTADA		30,298		29,160
Total product sales, net	$	99,481	$	91,842

The Company recorded research and development (“R&D”) revenue of $13.9 million and $17.5 million during the three months ended March 31, 2019 and 2018, respectively, related to its license and collaboration agreement with Biogen for Diroximel fumarate (“BIIB098”). The Company expects to earn an additional $77.6 million in R&D revenue under this agreement with Biogen through 2021.

Contract Assets—Contract assets include unbilled amounts resulting from sales under certain of the Company’s manufacturing contracts where revenue is recognized over time. The products included in the contract assets table below complete the manufacturing process in ten days to eight weeks. Contract assets are classified as current.

(In thousands)	Contract Assets
Contract assets at January 1, 2019	$	8,230
Additions		7,346
Transferred to receivables, net		(7,129	)
Contract assets at March 31, 2019	$	8,447

Contract Liabilities—Contract liabilities consist of contractual obligations related to deferred revenue.

(In thousands)	Contract Liabilities
Contract liabilities at January 1, 2019	$	12,694
Additions		1,516
Amounts recognized into revenue		(790	)
Contract liabilities at March 31, 2019	$	13,420