Software company SmartBear increased its office footprint by 16K SF at its Assembly Row headquarters, renewing its lease for another seven years.

SmartBear celebrated the expansion with a ribbon-cutting ceremony Thursday that was attended by Somerville Mayor Katjana Ballantyne. The company, which employs 260 workers, now occupies 52K SF on the third and fourth floors of 450 Artisan Way.

"We are proud to unveil our new corporate headquarters in Somerville today with its beautiful enhancements that will inspire work in a space that supports our sustainability, philanthropy, and diversity goals," Veronica Curran, chief people and culture officer at SmartBear, said in a press release.

SmartBear moved into its Somerville headquarters in 2015 and has 11 other locations globally.

In September, SmartBear Chief Financial Officer Shital Whitmore told the Boston Business Journal that the company will continue to hire out of Somerville and that company leaders "don't want to leave that area because our location is pretty key to get pretty good talent."

The 450 Artisan Way building, constructed in 2013, totals nearly 100K SF and has less than 10K SF available. Developed by Federal Realty, Assembly Row has more than 1M SF of office space, plus 1,500 residential units, a hotel and over 500K SF of retail.

The expansion comes as the Boston-area office market is in need of more demand growth, with vacancy rising to new highs in the third quarter. Many tenants are still hesitant to sign new leases, while others have shrunk their footprints or put space on the sublease market.