San Francisco -- Castlight Health, a San Francisco-based developer of software that makes cost and quality data for medical services available to employees through the web or mobile devices, said on Tuesday it has raised $100 million in its fourth round of funding. Participants included two unnamed mutual funds, as well as T. Rowe Price, Redmile Group and several previous backers. "By expanding our funding, we can respond to the growing demand for our solutions, seize major market opportunities, increase the breadth of our offerings and extend our reach," said co-founder and CEO Giovanni Colella. "We believe there is a huge opportunity to better engage companies and their employees as they make health care decisions." Castlight now has raised $181 million since its inception.