I find the above reasoning silly and lazy. There is no 18-month horizon in sell-side analyst models; to the contrary, sell-side analysts will project revenue and cash flow far into the future when it serves their needs to do do. Moreover, among NASH drug candidates only Ocaliva has a chance to be approved as soon as 2019, and it's a slim chance, IMHO.
The snippet you posted is a rudimentary outline of the bull case. The bear case for the NASH market is that patients won't have symptoms that drive them to seek medical attention until their disease is at a very late stage, so the penetration of the "addressable market" will be rather small.
I'm reserving judgment on how big the NASH market will be until:
• There are meaningful clinical data on combination regimens. (As one can tell from my recent posts on this board, I'm skeptical of ICPT's Ocaliva as a monotherapy, from both a regulatory and scientific standpoint.)
• There is sufficient progress in imaging technologies to enable NAFLD/NASH drugs to be prescribed without conducting liver biopsies.