The publicly listed company had revenue of US$322.4 million (A$449 million) for the financial year 2019.
The 24-year-old specialty pharmaceutical firm says it uses state-of-the-art, cGMP-compliant facilities to develop, manufacture, and market injectable, intra-nasal and inhalation products.
Amphastar has its headquarters in Rancho Cucamonga and also has five manufacturing facilities located in the US, China and Europe apart from a state-of-the-art New Drug Research Centre.
A screenshot of the list of files stolen from Amphastar.
"Amphastar’s long-standing relationship with the major group purchasing organisations, retailers and drug wholesalers in the US enables it to establish significant market share upon the introduction of its new products," it says on its website.
The criminals who staged the attack have apparently not had a positive response to their ransom demand.
Thus, they have released a list of files stolen from the business and also a list of the computers used by Amphastar, all of which run either Windows Server or Windows XP Professional.
iTWire has contacted the company for comment.
A screenshot of the list of computers at Amphastar.