Drug simulation software developer Simulations Plus Inc. announced Monday that it is acquiring Dilisym Services Inc. of Research Triangle Park, N.C. in a stock purchase agreement worth up to $10 million.

Under the terms of the deal, the Lancaster company will pay Dilisym shareholders $5 million upfront with $1 million of that held back for 18 months to pay any additional costs that may arise from the agreement.

The remaining $5 million can be earned over three years and is based on the profitability of the Dilisym division.

Dilisym, which provides drug-induced liver injury simulation software and related consulting services, will become a wholly owned subsidiary of Simulations Plus and continue operations under its brand name. The acquisition is expected to close on June 1.

As part of the deal, Simulations Plus’s employee count will increase by 11 to a total of 79. The company also anticipates adding more than $3 million in revenue to the combined company’s bottom line in fiscal year 2018.

“The combination will significantly strengthen our software and consulting services efforts and bolster our management team as well,” Walt Woltosz, Simulation Plus’s chief executive, said in a statement. “I am pleased that the existing management team of Dilisym Services will remain with the company.”

Simulations Plus (SLP) shares closed up 40 cents, or 3.4 percent, to $12.10 on the Nasdaq.