Genetic testing instrument maker Affymetrix Inc. reported a third-quarter loss Thursday because of declining sales and fewer one-time gains from note repurchases.

During the same period last year, the company recorded a one-time gain of $4.1 million, or 6 cents per share, from the repurchase of convertible notes.

Affymetrix reported a loss of $9.8 million, or 14 cents per share, compared with a profit of $968,000, or 1 cent per share, in the prior-year period. Revenue declined 18 percent to $57 million on lower sales of disposable testing accessories.

Analysts polled by FactSet expected a loss of 4 cents per share on revenue of $66.7 million.

CEO Frank Witney said the company is in the process of restructuring to increase profit margins.

"We reduced our headcount in R&D and plan to reallocate some of those resources to sales and marketing to help drive product adoption," Witney said.

Shares of Affymetrix Inc. fell 11 cents, or 2.2 percent, to $4.89 in afternoon trading.