NPS Pharmaceuticals (UNKNOWN:NPSP.DL) isn't hurting for good news. Even though the company announced a net loss of $0.16 per share, it still had plenty of positives to report with its second-quarter results announced after the market closed on Thursday. The market liked those positives, sending shares up over 20%. Here are the key things you need to know.

1. Royalties rolling in
The company reported revenue for the second quarter of $31.7 million. That reflects a year-over-year jump of 11.2%. By far, the biggest source of revenue came from royalties on Amgen's (NASDAQ:AMGN) sales of Sensipar/Mimpara. The calcium-reducing drug generated $28.9 million in revenue for NPS -- up 22% from the same period in 2012. However, $1.8 million of that total stemmed from a one-time favorable adjustment from Amgen.

NPS also received $2 million from Kyowa Hakko Kirin's sales of secondary hyperparathyroidism drug Regpara. This figure represented a drop from the $2.2 million recorded in the second quarter last year.

Johnson & Johnson (NYSE:JNJ) continues to sell narcotic pain reliever Nucynta, which generates royalties for NPS. However, the amount of Nucynta royalties combined with other miscellaneous royalties only totaled around $800,000, the same as the second quarter of 2012.

2. Gattex is galloping
The big news for NPS' revenues was strong performance from Gattex. Sales for the short bowel syndrome drug totaled $4.8 million during the second quarter.

NPS reported that as of Aug. 2, 141 patients are taking Gattex and 318 prescriptions have been received. Those numbers might seem low at first glance. But considering that short bowel syndrome is a rare disease and that Gattex was only launched this year, they're actually pretty good.

NPS plans to launch the drug in Europe in the first half of next year under the brand name Revestive. It thinks that with somewhere between 6,000 to 12,000 patients suffering from short bowel syndrome outside of the U.S., the international market for Gattex will be even bigger than in the U.S.

3. Natpara is near
NPS expects to submit its Biologic License Application, or BLA, for Natpara in the fourth quarter. Natpara treats hypoparathyroidism, a rare disease where the body produces insufficient parathyroid hormone.

If Natpara obtains approval, it should provide a nice bump to NPS' revenue. Some analysts project that the drug could top $250 million in peak annual sales.

The company also announced that it recently began enrolling patients in a study of hypoparathyroidism. Its goal is to follow patients for at least 10 years to "characterize the disorder under conditions of normal clinical practice."

Looking ahead
Based on the strong start for Gattex, the company now projects 2013 sales of $25 to $30 million. Amgen's sales of Sensipar are also showing solid growth. If NPS gains approval for Natpara, that will add yet another big revenue source.

NPS CEO Francois Nader projects a slower ramp-up in Europe for Gattex/Revestive. However, that shouldn't be too problematic with a larger potential market. All things considered, the future looks pretty bright for NPS Pharmaceuticals.