DETROIT (AP) — After reporting dismal first-quarter sales, Tesla is planning to lay off about a tenth of its workforce as it tries to cut costs, multiple media outlets reported Monday.

CEO Elon Musk detailed the plans in a memo sent to employees. The layoffs could affect about 14,000 of the 140,473 workers employed by the Austin, Texas, company at the end of last year.

Musk’s memo said that as Tesla prepares for its next phase of growth, “it is extremely important to look at every aspect of the company for cost reductions and increasing productivity,” The New York Times and CNBC reported. News of the layoffs was first reported by electric vehicle website Electrek.

Shares of Tesla fell 3% at the opening bell Monday after the news broke. They have lost about one-third of their value so far this year.

Tesla sales fell sharply last quarter as competition increased worldwide, electric vehicle sales growth slowed, and price cuts failed to draw more buyers. The company said it delivered 386,810 vehicles from January through March, nearly 9% below the 423,000 it sold in the same quarter of last year.