Zynga, the company best known for social media games like Facebook’s Farmville, is laying off nearly 20 percent of its current workforce. Zynga closed an office in Boston last fall, and will now close down its LA and New York and Dallas operations, according to AllThingsD.

So why is the gaming company struggling? Evelyn Rusli at the Wall Street Journal says Zynga has had a lot of problems — but a major one sticks out: 

“They were caught, essentially flat-footed, in the transition to mobile,” Rusli says, “and caught off guard by how fast people would adopt smartphones and switch their usage to smartphones as opposed to desktops.”

Some analysts hope Zynga might still do well by getting into legal online gambling.