Generic pharmaceuticals can be a tough industry, particular for smaller players that can experience dramatic fluctuations in quarterly earnings due to product shortages, price changes, and new competitive entrants, making these businesses exceptionally difficult for investors to value. Stability of cash flow is not a given for many larger companies like Mylan (MYL) and Teva (TEVA), let alone the likes of Amphastar (AMPH). I last wrote about the company in late 2017, and over that time period, shares are up just four percent in spite of multiple product approvals