Genesis Microchip ( GNSS) said earnings rose by a factor of five in its third quarter, handily beating estimates on a 50% sales surge.

The company also gave a fourth-quarter guidance range that encompasses the existing analysts' forecast. Investors nevertheless sold down the stock 4% to $20.69 after hours.

The semiconductor-for-imaging company earned $11.8 million, or 31 cents a share, in the latest quarter, compared with $2.1 million, or 6 cents a share, a year ago. Total revenue was $74.9 million, up from $50.1 million last year.

Backing out certain expenses, Genesis earned $11.8 million, or 31 cents a share, in the latest period, beating the Thomson First Call consensus by a dime. The top line was also ahead of analysts' $70.2 million projection.

For the fourth quarter, the company expects revenue of $72 million to $77 million, bookending the consensus estimate of $75.3 million.

Within the third quarter, Genesis shipped 4.3 million flat-panel television controller units, up 54% sequentially. It shipped 11.4 million LCD monitor controllers, up 6% from the second quarter. The company's gross margin rose 2.8 percentage points from the previous quarter.