Theranos chief executive Elizabeth Holmes (Glenn Chapman/Agence France-Presse via Getty Images)

The slow implosion of the blood-testing company Theranos continued in 2017 as the firm announced that it would lay off 40 percent of its employees in what it called a “further re-engineering.”

The company is laying off 155 employees, leaving “a core team of 220 professionals to execute on its business plans,” Theranos said in a statement on its website. The layoffs follow a round of deep job cuts in October, when Theranos laid off 340 employees and shuttered its clinical laboratories and wellness centers.

“These are always the most difficult decisions; however, this move allows Theranos to marshal its resources most efficiently and effectively,” the statement said.

Theranos has been struggling to get back on course after regulators found a slew of compliance issues over the past year and a half. Theranos voided two years of test results from its proprietary blood-testing device last year and lost a major business partner, Walgreens. It is being sued by patients and investors. Regulators have imposed harsh sanctions, including a two-year ban on Theranos chief executive Elizabeth Holmes owning or operating a clinical laboratory. The company has said it is appealing the decision.

In December, Theranos moved to bolster its corporate ranks, bringing in a medical device manufacturing expert and a corporate communications expert with a background in handling crises. Theranos added an expert in molecular diagnostics to its scientific and medical advisory board. Also in December, retired Marine Gen. James N. Mattis, who once pushed for the military to test the technology in the battlefield, left the company's board of directors.

A slimmed-down Theranos will now work to bring its miniLab testing platform to market, according to the statement. Holmes unveiled the blood-testing technology at a packed scientific conference session in the summer. The presentation disappointed a crowd of scientists who had hoped her presentation would reveal what exactly went wrong with a previous proprietary and highly secretive blood-testing device that had helped make the company one of the hottest start-ups in recent years.

“In the streamlined organization, teams have been aligned to meet product development, regulatory and commercial milestones,” the company said in a statement.