The quick calculations I did leave a range of 13 - 54 million in revenue to MNTA. The range in the Yahoo link is 10-50 million, so I can't say that the analysts are *that* far off.
The range is probably due to analysts guessing about what the margin is for NVS, for which I can't fault them.
Of course some of those within the range may have arrived there through incorrect calculations and faulty reimbursement provisions... ;-)