Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: After inching steadily upwards all day long, shares of Medivation (Nasdaq: MDVN) were up 10% at mid-afternoon.

So What: There's just one problem. I haven't a clue what is driving Medivation higher. Early this morning the company confirmed the timing of its Q1 earnings report and conference call (May 6 at 4:30 p.m. Stay tuned.) It also advised that its CFO will be giving a presentation at a Bank of America health care conference on May 11. But these hardly seem sufficient to justify a 10% bump in stock price.

Now What: Supposedly, CFO Clarence Machado will be updating investors on progress with its MDV3100 prostate cancer drug and dimebon Alzheimer's treatment -- but exactly what he'll be telling us about them remains a mystery. For now, all I can really tell you about the company is that: (A) it's not profitable, (B) no one on Wall Street expects it to become profitable any time soon, but (C) at least Medivation has $200 million or so in the bank to tide it over until it can begin making money on its own. 

Until then, I suspect we'll see the stock continue to bounce up and down for many years to come, twisting in the wind with every passing press release. Such is the fate of the biotech start-up investor.

Will Medivation give us any more to go on when it reports earnings next week? How about when it talks to Bank of America the week after? Add Medivation to your Watchlist and you'll be the first to know.