Supernus Pharmaceuticals Inc., which focuses on developing and commercializing products for the treatment of central nervous system diseases, reported fourth-quarter earnings doubled compared to the same quarter last year due to a spike in product sales.

Net income for the quarter reached $14.3 million, or 26 cents per share diluted, compared to $6.8 million, or 14 cents per share diluted, in the fourth quarter of last year.

Supernus beat analyst predictions for the quarter, which estimated 25 cents per share.

Revenue for the quarter rose to $62.4 million from $43.6 million in 2015, driven by growth in product sales.

Fourth-quarter net product sales were $61.1 million, an increase43 percent compared to 2015. Royalty and licensing revenue was consistent year to year.

Sales of the drugs Trokendi XR and Oxtellar XR totaled $136 million, a 22 percent increase over the fourth quarter of 2015.

The company expects to see sales growth in 2017. upernus advised investors that the company plans to report $265 million and $275 million in net product sales, up from $210 million last year.

Supernus will spend more on research and development in the coming year, allocating $55 million compared to $42.7 million last year.

The company’s stock price fell 3.56 percent, from $26.60 to $25.70, in Monday trading.

The 8-K can be found here.