Revenue

12 Months Ended

Dec. 31, 2021

Revenue

Revenue

9.  Revenue

	Year Ended December 31,
(in thousands)	2021		2020		2019
Product revenue, net	$	23,386	$	108	$	1,538
Collaboration revenues		3,830		2,756		6,210
Research premium and grant revenue		1,679		2,163		1,733
Total revenue	$	28,895	$	5,027	$	9,481

Collaboration revenues for the year ended December 31, 2021 include $2.6 million related to the restructured China Region License Agreement, a portion of which is recognized over the estimated period the manufacturing collaboration and regulatory support will be provided to Sumitomo Pharmaceuticals (Suzhou), as well as $1.2 million of the Company’s share of revenues associated with the SIVEXTRO distribution agreement with Merck & Co., Inc. through April 11, 2021 (see Note 14). Collaboration revenues for the year ended December 31, 2020 includes a $0.5 million regulatory milestone payment from Sunovion, $1.8 million for the Company´s share of revenues associated with the SIVEXTRO distribution agreement with Merck & Co., Inc., as well as collaboration revenues associated with the restructuring of the China Region License Agreement. Collaboration revenues for the year ended December 31, 2019 includes a $1.0 million upfront payment under the Sunovion License Agreement received in April 2019, and a $5.0 million milestone payment under the China Region License Agreement.

The Company sells its products to pharmaceutical wholesalers/distributors (i.e., the Company’s customers). The Company’s wholesalers/distributors in turn sell the Company’s products directly to clinics, hospitals, and private practices. Revenue from the Company’s product sales is recognized as physical delivery of product occurs (when the Company’s customer obtains control of the product), in return for agreed-upon consideration.

SIVEXTRO product revenues, net of gross-to-net accruals and adjustments for returns were $23.8 million since the Company began exclusive distribution of SIVEXTRO under its own National Drug Code, or NDC, on April 12, 2021. For the years ended December 31, 2021, 2020 and 2019 XENLETA product revenues, net of gross-to-net accruals and adjustments for returns, were $(0.4) million, $0.1 million and $1.5 million, respectively, including revenues from the Company´s Named Patient Program of $17,000 for the year ended December 31, 2021. The Company´s gross-to-net, or GTN, estimates are based upon information received from external sources (such as written or oral information obtained from the Company´s customers with respect to their period-end inventory levels and sales to end-users during the period), in combination with management’s informed judgments. Due to the inherent uncertainty of these estimates, the actual amount incurred may be materially above or below the amount initially estimated when product revenues are originally recorded, then requiring prospective adjustments to the Company’s reported product revenues, net.

For the year ended December 31, 2021, the Company recorded a $1.3 million returns reserve adjustment for shelf life expiration of certain XENLETA products. For the year ended December 31, 2020, the Company recorded a returns reserve adjustment of $0.4 million for slow-moving inventory, representing 50% of XENLETA IV inventory held at its Specialty Distributors, as well as an adjustment for returns from a single mail order specialty pharmacy.