Item 2. Properties

We lease a total of approximately 143,000 square feet of office space, laboratory, warehousing and other related facilities. Approximately 100,000 of the total square footage consists of laboratory and office space for our corporate headquarters in Billerica, Massachusetts under leases expiring in November 2022.

Additionally, we lease approximately 29,000 square feet of warehousing space in Billerica, Massachusetts under a lease expiring in September 2019. We lease other facilities in Canada, China, the United Kingdom, California and Tennessee containing a total of approximately 14,000 square feet under leases expiring from April 2018 to December 2020.

In December 2016, we purchased property for our U.S. manufacturing facility in Acton, Massachusetts. The property includes 195,000 square feet of manufacturing and office space.