Days after warning he would move Tesla Inc.’s headquarters out of California and may cease manufacturing in the state, Elon Musk wrote a thank-you note to employees for reopening the company’s only U.S. car plant.

“Just wanted to send you a note of appreciation for working hard to make Tesla successful,” the chief executive officer wrote in an email to employees seen by Bloomberg News. “It is so cool seeing the factory come back to life and you are making it happen!!”

Musk, 48, said Monday that Tesla (TSLA) was restarting production at its plant in Fremont, California, flouting county officials who ordered the company to stay closed and openly acknowledging he was risking arrest for himself and his employees. When asked on Twitter how the day went at the factory, Musk replied: “Great.”

To follow through on his tweets claiming Tesla would move its headquarters and future programs to Nevada or Texas, the CEO would have to uproot many of the roughly 20,000 employees the electric-car maker has in the San Francisco Bay area. About half of the company’s headcount is at the factory. Musk tweeted Saturday that Tesla would decide whether to keep manufacturing in Fremont based on how Tesla is treated in the future.