Business	6 Months Ended
Jun. 30, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Business	1. Business Cara Therapeutics, Inc., or the Company, is a clinical-stage biopharmaceutical corporation formed on July 2, 2004. The Company is focused on developing and commercializing new chemical entities designed to alleviate pruritus by selectively targeting peripheral kappa opioid receptors. The Company’s primary activities to date have been organizing and staffing the Company, developing its product candidates and raising capital. As of June 30, 2019, the Company had raised aggregate net proceeds of approximately $383,200 from several rounds of equity financing, including its initial public offering, or IPO, which closed in February 2014 and three follow-on public offerings of common stock, which closed in July 2018, April 2017 and August 2015, and the issuance of convertible preferred stock and debt prior to the IPO. The Company had also received $88,900 under its license agreements for CR845/difelikefalin, primarily with Vifor Fresenius Medical Care Renal Pharma Ltd., or VFMCRP, Maruishi Pharmaceutical Co. Ltd., or Maruishi, and Chong Kun Dang Pharmaceutical Corp., or CKDP, and an earlier product candidate for which development efforts ceased in 2007. Additionally, in May 2018, the Company received net proceeds of $14,556 from the issuance and sale of 1,174,827 shares of the Company’s common stock to Vifor (International) Ltd., or Vifor, in connection with the Company’s license agreement with VFMCRP (see Note 10, Collaboration and Licensing Agreements). As of June 30, 2019, the Company had unrestricted cash and cash equivalents and marketable securities of $135,629 and an accumulated deficit of $339,274. The Company has incurred substantial net losses and negative cash flows from operating activities in nearly every fiscal period since inception and expects this trend to continue for the foreseeable future. The Company recognized net losses of $22,960 and $17,194 for the three months ended June 30, 2019 and 2018, respectively, and $44,920 and $33,961 for the six months ended June 30, 2019 and 2018, respectively, and had net cash (used in) provided by operating activities of $(52,422) and $22,552 for the six months ended June 30, 2019 and 2018, respectively. In July 2019, the Company received net proceeds of approximately $136,446 from the issuance and sale of 6,325,000 shares of its common stock in a follow-on public offering, which includes the full exercise of the underwriters’ option to purchase 825,000 additional shares of its common stock (see Note 16, Subsequent Events). The Company is subject to risks common to other life science companies including, but not limited to, uncertainty of product development and commercialization, lack of marketing and sales history, development by its competitors of new technological innovations, dependence on key personnel, market acceptance of products, product liability, protection of proprietary technology, ability to raise additional financing, and compliance with Food and Drug Administration, or FDA, and other government regulations. If the Company does not successfully commercialize any of its product candidates, it will be unable to generate recurring product revenue or achieve profitability.

Business

6 Months Ended

Jun. 30, 2019

Organization Consolidation And Presentation Of Financial Statements [Abstract]

1. Business

Cara Therapeutics, Inc., or the Company, is a clinical-stage biopharmaceutical corporation formed on July 2, 2004. The Company is focused on developing and commercializing new chemical entities designed to alleviate pruritus by selectively targeting peripheral kappa opioid receptors. The Company’s primary activities to date have been organizing and staffing the Company, developing its product candidates and raising capital.

As of June 30, 2019, the Company had raised aggregate net proceeds of approximately $383,200 from several rounds of equity financing, including its initial public offering, or IPO, which closed in February 2014 and three follow-on public offerings of common stock, which closed in July 2018, April 2017 and August 2015, and the issuance of convertible preferred stock and debt prior to the IPO. The Company had also received $88,900 under its license agreements for CR845/difelikefalin, primarily with Vifor Fresenius Medical Care Renal Pharma Ltd., or VFMCRP, Maruishi Pharmaceutical Co. Ltd., or Maruishi, and Chong Kun Dang Pharmaceutical Corp., or CKDP, and an earlier product candidate for which development efforts ceased in 2007. Additionally, in May 2018, the Company received net proceeds of $14,556 from the issuance and sale of 1,174,827 shares of the Company’s common stock to Vifor (International) Ltd., or Vifor, in connection with the Company’s license agreement with VFMCRP (see Note 10, Collaboration and Licensing Agreements).

As of June 30, 2019, the Company had unrestricted cash and cash equivalents and marketable securities of $135,629 and an accumulated deficit of $339,274. The Company has incurred substantial net losses and negative cash flows from operating activities in nearly every fiscal period since inception and expects this trend to continue for the foreseeable future. The Company recognized net losses of $22,960 and $17,194 for the three months ended June 30, 2019 and 2018, respectively, and $44,920 and $33,961 for the six months ended June 30, 2019 and 2018, respectively, and had net cash (used in) provided by operating activities of $(52,422) and $22,552 for the six months ended June 30, 2019 and 2018, respectively.

In July 2019, the Company received net proceeds of approximately $136,446 from the issuance and sale of 6,325,000 shares of its common stock in a follow-on public offering, which includes the full exercise of the underwriters’ option to purchase 825,000 additional shares of its common stock (see Note 16, Subsequent Events).

The Company is subject to risks common to other life science companies including, but not limited to, uncertainty of product development and commercialization, lack of marketing and sales history, development by its competitors of new technological innovations, dependence on key personnel, market acceptance of products, product liability, protection of proprietary technology, ability to raise additional financing, and compliance with Food and Drug Administration, or FDA, and other government regulations. If the Company does not successfully commercialize any of its product candidates, it will be unable to generate recurring product revenue or achieve profitability.