Organization and Nature of Operations	12 Months Ended
Dec. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Organization and Nature of Operations	Note 1—Organization and Nature of Operations Ra Medical Systems, Inc. (the “Company”) was formed in September 4, 2002, in the state of California and reincorporated in Delaware on July 14, 2018. The Company is a medical device company that develops, manufactures and markets advanced excimer lasers for use in the treatment of vascular and dermatological diseases. The Company’s product development centers around proprietary applications of its advanced excimer laser technology for use as a tool in the treatment of peripheral artery disease (“PAD”) and psoriasis, vitiligo, atopic dermatitis and leukoderma. Reincorporation—In July 2018, the Company reincorporated in Delaware, the par value of each share of common stock was established to be $0.0001 and the number of authorized shares of common stock was increased from 10,000,000 to 25,000,000. In connection with the reincorporation, common stock and additional paid-in capital amounts in these financial statements have been adjusted to reflect the par value of common stock. All share information included in these financial statements has been adjusted to reflect this reincorporation. Initial Public Offering—On October 1, 2018, the Company closed its initial public offering ("IPO") of 4,485,000 shares of common stock at an offering price to the public of $17.00 per share, resulting in gross proceeds of approximately $76.2 million. These amounts include the exercise in full by the underwriters of their option to purchase 585,000 additional shares of common stock at the same price to the public to cover over-allotments. The aggregate net proceeds to the Company from its IPO were $67.3 million after deducting the underwriters discount and offering costs of $5.3 million and $3.6 million, respectively. The Company’s registration statement on Form S-1 relating to its IPO was declared effective by the Securities and Exchange Commission on September 26, 2018. In connection with the IPO, the Company filed an Amended and Restated Certificate of Incorporation which authorizes the issuance of 300,000,000 shares of common stock with a par value of $0.0001 and 10,000,000 shares of preferred stock with a par value of $0.0001. Going Concern — The financial statements have been prepared on a going concern basis, which contemplates the realization of assets and settlement of liabilities in the normal course of business, and do not include any adjustments to reflect the possible future effects on the recoverability and classification of assets or amounts and classification of liabilities that may result from the outcome of this uncertainty. The Company has experienced recurring net losses from operations and negative cash flows from operating activities, has a significant accumulated deficit and expects to continue to incur net losses into the foreseeable future. The Company had an accumulated deficit of $117.2 million at December 31, 2019. In 2019, the Company used $33.2 million for operating activities. As of December 31, 2019, the Company had cash, cash equivalents and short-term investments of $30.6 million. Management expects operating losses and negative cash flows to continue for the foreseeable future with the Company’s reduced commercial footprint, and as the Company continues to incur costs related to its atherectomy clinical trial, engineering efforts to improve the shelf-life of its catheters and develop next generation products and legal costs associated with ongoing litigation. Management estimates that based on the Company’s liquidity resources, there is substantial doubt about the Company’s ability to continue as a going concern within 12 months from the date of issuance of the financial statements. Management’s ability to continue as a going concern is dependent upon its ability to raise additional funding. Management’s plans to raise additional capital through public or private equity or debt financings to fulfill its operating and capital requirements for at least 12 months from the date of the issuance of the financial statements. However, the Company may not be able to secure such financing in a timely manner or on favorable terms, if at all. Furthermore, if the Company issues equity securities to raise additional funds, its existing stockholders may experience dilution, and the new equity securities may have rights, preferences and privileges senior to those of the Company’s existing stockholders.

Organization and Nature of Operations

12 Months Ended

Dec. 31, 2019

Organization Consolidation And Presentation Of Financial Statements [Abstract]

Note 1—Organization and Nature of Operations

Ra Medical Systems, Inc. (the “Company”) was formed in September 4, 2002, in the state of California and reincorporated in Delaware on July 14, 2018. The Company is a medical device company that develops, manufactures and markets advanced excimer lasers for use in the treatment of vascular and dermatological diseases. The Company’s product development centers around proprietary applications of its advanced excimer laser technology for use as a tool in the treatment of peripheral artery disease (“PAD”) and psoriasis, vitiligo, atopic dermatitis and leukoderma.

Reincorporation—In July 2018, the Company reincorporated in Delaware, the par value of each share of common stock was established to be $0.0001 and the number of authorized shares of common stock was increased from 10,000,000 to 25,000,000. In connection with the reincorporation, common stock and additional paid-in capital amounts in these financial statements have been adjusted to reflect the par value of common stock. All share information included in these financial statements has been adjusted to reflect this reincorporation.

Initial Public Offering—On October 1, 2018, the Company closed its initial public offering ("IPO") of 4,485,000 shares of common stock at an offering price to the public of $17.00 per share, resulting in gross proceeds of approximately $76.2 million. These amounts include the exercise in full by the underwriters of their option to purchase 585,000 additional shares of common stock at the same price to the public to cover over-allotments. The aggregate net proceeds to the Company from its IPO were $67.3 million after deducting the underwriters discount and offering costs of $5.3 million and $3.6 million, respectively. The Company’s registration statement on Form S-1 relating to its IPO was declared effective by the Securities and Exchange Commission on September 26, 2018.

In connection with the IPO, the Company filed an Amended and Restated Certificate of Incorporation which authorizes the issuance of 300,000,000 shares of common stock with a par value of $0.0001 and 10,000,000 shares of preferred stock with a par value of $0.0001.

Going Concern — The financial statements have been prepared on a going concern basis, which contemplates the realization of assets and settlement of liabilities in the normal course of business, and do not include any adjustments to reflect the possible future effects on the recoverability and classification of assets or amounts and classification of liabilities that may result from the outcome of this uncertainty.

The Company has experienced recurring net losses from operations and negative cash flows from operating activities, has a significant accumulated deficit and expects to continue to incur net losses into the foreseeable future. The Company had an accumulated deficit of $117.2 million at December 31, 2019. In 2019, the Company used $33.2 million for operating activities. As of December 31, 2019, the Company had cash, cash equivalents and short-term investments of $30.6 million. Management expects operating losses and negative cash flows to continue for the foreseeable future with the Company’s reduced commercial footprint, and as the Company continues to incur costs related to its atherectomy clinical trial, engineering efforts to improve the shelf-life of its catheters and develop next generation products and legal costs associated with ongoing litigation.

Management estimates that based on the Company’s liquidity resources, there is substantial doubt about the Company’s ability to continue as a going concern within 12 months from the date of issuance of the financial statements.

Management’s ability to continue as a going concern is dependent upon its ability to raise additional funding. Management’s plans to raise additional capital through public or private equity or debt financings to fulfill its operating and capital requirements for at least 12 months from the date of the issuance of the financial statements. However, the Company may not be able to secure such financing in a timely manner or on favorable terms, if at all. Furthermore, if the Company issues equity securities to raise additional funds, its existing stockholders may experience dilution, and the new equity securities may have rights, preferences and privileges senior to those of the Company’s existing stockholders.