Rethink Robotics, the Boston company that pioneered the development of “cobots” —collaborative robots designed to work alongside humans — shut down on Wednesday.

The company’s closure was abrupt and surprised members of the robotics community. According to the Boston Globe, Rethink had been exploring a deal to sell itself to another firm, but the acquisition fell through at the last minute. “We thought that we had a deal that we were going to be able to close,” Rethink chief executive Scott Eckert told the Globe.

Ecekert declined to name the company involved in the failed acquisition, but said that Rethink had been running low on cash after disappointing sales of its Baxter and Sawyer robots. We’ve reached out to Rethink and will update this story if we hear more.

Rethink was founded in 2008 by Rodney Brooks and Ann Whitaker. It introduced its first product, the Baxter robot, in 2011; followed by Sawyer, a smaller, faster version, in 2015. The robots were intended to usher in a new age of automation; one where machines would work safely next to humans, rather than confined to their own sections on the factory floor.

“We got out a little early with a very, very innovative product.”

Both Baxter and Sawyer used animated faces to communicate with their co-workers, and could be programmed without specialist knowledge. Workers could simply guide the robots’ dextrous arms to perform a specific task and the bots would remember what to do. This ease of use, combined with the bots’ safety features, also made them popular in research labs.

“We are innovators, pioneers, in fact credited largely with creating the collaborative robot category in the first place,” Eckert told the Globe, adding that Rethink might also have been ahead of its time. “We got out a little early with a very, very innovative product, and unfortunately did not get the commercial success that we expected to get.”

Rethink was not the only company offering collaborative robots either. Rivals include Danish firm Universal Robots, which also sells safe and easy-to-program collaborative robots while offering a larger ecosystem of hardware (like different gripping tools for the robots’ arms).

“Baxter maybe didn’t do as well in the marketplace (and) Sawyer was maybe playing catch-up,” Jeff Burnstein, president of robotic trade group the Association for Advancing Automation, told the Boston Globe. “It’s tough to compete with Universal.”

Rethink will now be selling off its intellectual property and patent portfolio, with 91 employees let go. The company is the second major robotics firm to close in recent months, with Mayfield Robotics, makers of the social robot Kuri, shutting down in August.

Rethink’s chief executive Eckert says that the company’s closure is not indicative of wider troubles in the industry. “I think history will say we changed industrial robots for ever,” said Eckert. “We showed the world that robots could safely work side by side with people.”