Shares of Cree ( CREE) plummeted in after-hours trading Wednesday after the semiconductor materials company reduced its fourth-quarter earnings projection due to lower light-emitting diode sales. Cree expects to post earnings below its previously announced target range of 22 cents to 24 cents a share. The company estimates revenue of $106.7 million for the quarter ended June 25, compared with its earlier forecast of $106 million to $110 million. Analysts polled by Thomson First Call were expecting earnings of 23 cents a share and a top line of $107.3 million. Gross margin for the quarter is expected to be about 42%, below Cree's previously targeted range of 46% to 47%. For the first quarter, the company expects LED chip sales may decline slightly from the fourth quarter due to a recent slowdown in demand for mobile products. Cree said, however, that this decline should be mostly offset by increased sales of the company's XLamp LED and Schottky diode products. Cree is due to report full fourth-quarter earnings on Aug. 10. Shares fell $5.42, or 24%, to $17.17 after hours. Tekelec ( TKLC) shares tumbled after the telecommunications product maker posted weaker-than-expected first-quarter revenue. The company reported an adjusted loss of $9.8 million, or 15 cents a share, on $107.5 million in sales for the quarter ended in March. Those numbers compare with a year-earlier profit of $20.6 million, or 28 cents a share, on revenue of $139 million. Analysts anticipated earnings of 14 cents a share and sales of $145.1 million. Tekelec said operating results and gross margins were hurt by lower revenue from its higher margin products and pricing pressure. Shares fell $1.59, or 14%, to $10.10 after hours. Resources Connection ( RECN) retreated after the management services company posted mixed fourth-quarter results. The company's income for the quarter ended May 31 was roughly flat at $15.7 million, or 31 cents a share. Revenue climbed 11% to $165.9 million. The earnings matched Wall Street's estimate of 31 cents a share, but the revenue fell short of analysts' target of $166.7 million. After hours, shares declined 39 cents, or 1.6%, to 23.97.