The pharma company plans to use the Signatera assay to determine whether it can identify patients who will respond to immunotherapy.
CareDx and Invitae each had massive share-price gains last month. Exact Sciences, GenMark, and Natera also saw sizeable increases in their stock prices.
The Signatera research-use-only assay monitors cancer treatment and assesses minimal residual disease, and is customized for individual patients.
The firm is working on harnessing its ability to assess fetal fraction to develop new methods to predict fetal aneuploidy risks and pregnancy complications.
The firm recognized $63.1 million in revenues and processed 162,807 tests in the second quarter 2018.
Natera, Invitae, and Opko Health were the biggest gainers in the 360Dx Index last month, while Enzo Biochem had the steepest decline.
The firm said it will offer 4.5 million shares of its common stock at $20 per share. It expects to close its follow-on public offering on July 16.
The molecular diagnostics company previously raised $180 million in its 2015 initial public offering.
Month over month, the 360Dx Index beat the Dow Jones Industrial Average, the Nasdaq Composite, and the Nasdaq Biotech Index.
The company outlined its plans to launch a kidney transplant rejection test that is based on cell-free DNA in 2019 and described its progress in breast cancer research.