Highly volatile biopharmaceutical company MannKind (MNKD -0.36%) delivered its fourth-quarter earnings results before the opening bell this morning. Results point to higher costs as it readies for a PDUFA decision in April for the company's inhalable type 1 and 2 diabetes mellitus drug, Afrezza.

For the quarter, MannKind reported total operating expenses of $46.6 million, which is an increase of 39% from the $33.5 million in expenses reported in the comparable quarter last year. Research and development expenses rose nearly 15% to $29 million as a $4.3 million increase in noncash stock compensation offset a $1.3 million drop in clinical trial related expenses. Selling, general, and administrative expenses soared 115% to $17.6 million, primarily because of a $6 million increase in noncash stock compensation and a $2.2 million increase in professional legal and finance fees.

MannKind did not report any revenue for the quarter or fiscal 2013.

In total, inclusive of interest expensing, MannKind's net loss widened to $53.58 million from $51.78 million in the year-ago quarter. However, its earnings-per-share loss shrank to just $0.16 from a loss of $0.23 per share, as it had 98.05 million more shares outstanding now than at the fourth quarter of 2012.

Since MannKind is a wholly clinical-stage company at the moment, cash burn is also important. It ended the quarter and year with $70.79 million in cash and cash equivalents, up from $61.84 million in the year-ago period, and had an additional $30.1 million borrowing capacity available to it

All eyes will now turn to April 15, the date for Food and Drug Administration to levy an approval or complete response letter for Afrezza.