Description of Business	3 Months Ended
Mar. 31, 2016
Description of Business
Description of Business	1. Description of Business TESARO, Inc., or the Company or TESARO, was incorporated in Delaware on March 26, 2010 and commenced operations in May 2010. Headquartered in Waltham, Massachusetts, TESARO is an oncology-focused biopharmaceutical company dedicated to improving the lives of cancer patients. TESARO acquires, in-licenses, develops, and commercializes oncology products and product candidates. Since incorporation, primary activities have consisted of acquiring product candidates, advancing development of these product candidates, developing intellectual property, recruiting personnel and raising capital. As part of its business strategy, the Company intends to continue to in-license or acquire additional product candidates across various stages of development. The Company operates in one segment. The Company is subject to a number of risks, including dependence on key individuals, the need to develop commercially viable products, competition from other companies, many of which are larger and better capitalized, and the need to obtain adequate additional financing to fund the development and potential commercialization of its product candidates and further its in-licensing and acquisition activities. On September 1, 2015, the Company’s first commercial product, VARUBI® (rolapitant), was approved by the United States Food and Drug Administration, or FDA, in combination with other antiemetic agents in adults for the prevention of delayed nausea and vomiting associated with initial and repeat courses of emetogenic cancer chemotherapy, including, but not limited to, highly emetogenic chemotherapy. The Company commenced sales of VARUBI during the fourth quarter of 2015. The Company has incurred significant operating losses since inception and has relied on its ability to fund its operations through private and public equity and debt financings. Management expects operating losses and negative operating cash flows to continue for the foreseeable future. As the Company continues to incur losses, transition to profitability is dependent upon the successful development, approval, and commercialization of its products and product candidates and the achievement of a level of revenues adequate to support its cost structure. The Company may never achieve profitability, and unless and until it does, the Company will continue to need to raise additional capital. On March 18, 2016, the Company closed a private placement of its common stock with certain accredited investors, whereby an aggregate of 4,404,658 shares of common stock were issued at a price per share of $35.19 for aggregate gross proceeds of approximately $155.0 million. On April 5, 2016, the Company closed a private placement of its common stock with one accredited investor for gross proceeds of approximately $50.0 million. Management intends to fund future operations in part through the proceeds from these financings and additional public or private equity or debt offerings and may seek additional capital through arrangements with strategic partners or from other sources.

1. Description of Business

TESARO, Inc., or the Company or TESARO, was incorporated in Delaware on March 26, 2010 and commenced operations in May 2010. Headquartered in Waltham, Massachusetts, TESARO is an oncology-focused biopharmaceutical company dedicated to improving the lives of cancer patients. TESARO acquires, in-licenses, develops, and commercializes oncology products and product candidates. Since incorporation, primary activities have consisted of acquiring product candidates, advancing development of these product candidates, developing intellectual property, recruiting personnel and raising capital. As part of its business strategy, the Company intends to continue to in-license or acquire additional product candidates across various stages of development. The Company operates in one segment. The Company is subject to a number of risks, including dependence on key individuals, the need to develop commercially viable products, competition from other companies, many of which are larger and better capitalized, and the need to obtain adequate additional financing to fund the development and potential commercialization of its product candidates and further its in-licensing and acquisition activities.

On September 1, 2015, the Company’s first commercial product, VARUBI® (rolapitant), was approved by the United States Food and Drug Administration, or FDA, in combination with other antiemetic agents in adults for the prevention of delayed nausea and vomiting associated with initial and repeat courses of emetogenic cancer chemotherapy, including, but not limited to, highly emetogenic chemotherapy. The Company commenced sales of VARUBI during the fourth quarter of 2015.

The Company has incurred significant operating losses since inception and has relied on its ability to fund its operations through private and public equity and debt financings. Management expects operating losses and negative operating cash flows to continue for the foreseeable future. As the Company continues to incur losses, transition to profitability is dependent upon the successful development, approval, and commercialization of its products and product candidates and the achievement of a level of revenues adequate to support its cost structure. The Company may never achieve profitability, and unless and until it does, the Company will continue to need to raise additional capital. On March 18, 2016, the Company closed a private placement of its common stock with certain accredited investors, whereby an aggregate of 4,404,658 shares of common stock were issued at a price per share of $35.19 for aggregate gross proceeds of approximately $155.0 million. On April 5, 2016, the Company closed a private placement of its common stock with one accredited investor for gross proceeds of approximately $50.0 million. Management intends to fund future operations in part through the proceeds from these financings and additional public or private equity or debt offerings and may seek additional capital through arrangements with strategic partners or from other sources.