Phal spikes will last quite a while once they're cut. New buds may keep "developing" but, it's been my experience that these will usually just blast after they reach any size.
Why don't you try stem-propping it? Cut the spike again one node up from where it's cut now (just under the next "joint"), dip the end in a rooting hormone like RootTone, and put it in a little pot of sphagnum. Keep the sphagnum damp at all times, and there's a good chance that, in a month and a half or so, the spike will develop a little baby plant!