After hours trading volume is always low and it can be misleading (Jim Cramer once called it "the badlands"), but I'm concerned that the latest trade in MTSN was $3.59, and the current bid/ask is $2.90/$3.40. We won't really know how the market is going to respond to the quarterly report and the conference call until the main market opens on Friday morning and the big players have a chance to trade.
IMS is a market research company (e.g. like Nielsen) that tracks and reports back to manufacturers how many prescriptions are being written for each drug. Nielsen does similar work for all of the consumer items sold in grocery stores and other outlets. I do not have access to their data.