Valencia-based diabetes drug developer MannKind Inc. lost $50.8 million in the third quarter of 2013 (17 cents per share), widening the gap from 2012’s third-quarter loss of $42.8 million (22 cents per share, with fewer shares outstanding).

The company attributed much of the difference to a “non-cash stock compensation expense of $6.7 million in the third quarter of 2013.”

Analysts were expecting a narrower loss of 15 cents per share.

MannKind has been in the research-and-development phase since the company was founded by billionaire Alfred Mann. Last month it again filed for FDA approval of its candidate diabetes medicine, an inhalable insulin called Afrezza. The FDA refused to sign off two years ago, saying more clinical trials were needed. The trials have been completed.

The company said it spent $27.3 million on R&D during the third quarter of 2013, versus $25.5 million a year earlier, primarily due to that “increase in non-cash stock compensation expense,” which was partially offset by lower costs of clinical trials since they’re done now.

Total operating expenses were $44.8 million, up $9.3 million from the prior-year quarter’s $35.5 million.

Also last month, Alfred Mann extended the maturity of his loan to the company to Jan. 5, 2020, with a draw-down deadline of Dec. 31, 2019.