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What happened

Investors in Sarepta Therapeutics (SRPT -2.12%) are having another great day. Shares of the rare-disease focused biotech are up more than 12% as of 11:50 a.m. EDT Tuesday in the wake of catching a handful of analyst upgrades.

So what

Wall Street was caught off guard on Monday after news broke that the FDA had granted accelerated approval of Sarepta's Duchenne muscular dystrophy (DMD) drug Exondys 51. In response, analysts having been tripping over themselves in the last 24 hours to upgrade the company's shares. 

On Monday, at least three separate analysts raised their rating. The most dramatic change came from RBC Capital Markets. The investment firm upgraded its outlook to "outperform" and changed its price target to $83. That's far higher than its prior target of $5.

The good news kept rolling in on Tuesday, too. Needham reiterated its "buy" rating and raised its price target to $81. That's also substantially higher than its prior outlook of just $47.

When you combine the love pouring in from Wall Street with the company's extremely high short-ratio -- roughly 35% of Sarepta's shares have been sold short -- it's no surprise to see the company's stock moving higher.

Now what

Sarepta held a special conference call with investors on Monday evening to share more details about its commercialization plans. The company plans on selling Exondy's 51 in two different formats -- 2 mL and 10 mL -- and have announced a list price of $1,600 and $8,000, respectively, for each. That puts the annual cost of treatment at about $300,000 per patient, which is consistent with the pricing that PTC Therapeutics receives for the sale of its DMD drug Translarna in the E.U.

Management also stated on the call that they will be "exploring the sale" of the rare pediatric disease priority review voucher that they were awarded as part of the approval. Last year pharma giant AbbVie ponied up $350 million to get its hands on one of those vouchers, so this could be a significant source of non-dilutive funding for Sarepta.

Sarepta also stated that its team of national account managers will be opening up dialogues with payers to get the reimbursement process rolling. The company expects it to take 30 to 90 days for interested patients to receive coverage, which will create a small lag in the company's ability to recognize revenue.

All in all, there's a lot going on at Sarepta right now and new information is coming out every day. That hints that this company's stock is likely to remain volatile for the foreseeable future, so bulls and bears should plan accordingly.