Subsequent Event	12 Months Ended
Dec. 31, 2021
Subsequent Event [Abstract]
Subsequent Event	16. Subsequent Events On January 7, 2022, the Company filed with the Secretary of State of the State of Delaware a certificate of amendment, or the Certificate of Amendment, to the Company’s Amended and Restated Certificate of Incorporation, to increase the number of shares of common stock authorized for issuance from 150,000,000 shares to 300,000,000 shares. The Certificate of Amendment was effective upon filing, and was approved at a special meeting of stockholders (the “Special Meeting”) of the Company held on January 7, 2022. On January 7, 2022, the Company and Perceptive entered into the Second Amendment (see Note 9). On January 7, 2022, the Company prepaid $5.0 million of the outstanding debt, and in accordance with the terms of the Second Amendment, no prepayment premium was due with the prepayment. On March 10, 2022, the Company and Perceptive entered into a third amendment to the Perceptive Credit Agreement, as amended (the “Third Amendment”). The Third Amendment waived the Company’s obligations to (1) comply with certain financial covenants relating to minimum revenue requirements through September 30, 2022, conditioned upon the satisfaction of certain conditions, including the Company raising additional capital and prepaying a portion of its outstanding debt by April 30, 2022 and (2) file financial statements along with its Annual Report on Form 10-K for the fiscal year ended December 31, 2021 that are not subject to any “going concern” qualification. On March 13, 2022, the Company entered into a Securities Purchase Agreement (the “Purchase Agreement”) with a single healthcare-focused institutional investor (the “Purchaser”), pursuant to which the Company issued, in a registered direct offering (the “2022 Preferred Stock Offering”), 2,425 shares of Series A convertible preferred stock (the “Series A Preferred Stock”) and 2,425 shares of Series B convertible preferred stock (the “Series B Preferred Stock”) and Series A warrants (the “Series A Warrants”) to purchase up to an aggregate of 24,250,000 shares of the common stock of the Company (the “Common Stock”) and Series B warrants (the “Series B Warrants”) to purchase up to an aggregate of 24,250,000 shares of Common Stock. Each share of Series A Preferred Stock and Series B Preferred Stock has a stated value of $1,000 per share and a conversion price of $0.20 per share. The shares of preferred stock issued in the offering are convertible into an aggregate of 24,250,000 shares of Common Stock. The Series A Warrants have an exercise price of $0.26 per share, will become exercisable six months following the date of issuance, and will expire 5 years following the initial exercise date. The Series B Warrants have an exercise price of $0.26 per share, will become exercisable six months following the date of issuance, and will expire one and one-half years following the initial exercise date. The Purchase Agreement contains customary representations and warranties and agreements of the Company and the Purchaser and customary indemnification rights and obligations of the parties. Total gross proceeds from the 2022 Preferred Stock Offering, before deducting the placement agent's fees and other estimated offering expenses, are $4.9 million. The 2022 Preferred Stock Offering closed on March 14, 2022.

Subsequent Event

12 Months Ended

Dec. 31, 2021

16. Subsequent Events

On January 7, 2022, the Company filed with the Secretary of State of the State of Delaware a certificate of amendment, or the Certificate of Amendment, to the Company’s Amended and Restated Certificate of Incorporation, to increase the number of shares of common stock authorized for issuance from 150,000,000 shares to 300,000,000 shares. The Certificate of Amendment was effective upon filing, and was approved at a special meeting of stockholders (the “Special Meeting”) of the Company held on January 7, 2022.

On January 7, 2022, the Company and Perceptive entered into the Second Amendment (see Note 9). On January 7, 2022, the Company prepaid $5.0 million of the outstanding debt, and in accordance with the terms of the Second Amendment, no prepayment premium was due with the prepayment.

On March 10, 2022, the Company and Perceptive entered into a third amendment to the Perceptive Credit Agreement, as amended (the “Third Amendment”). The Third Amendment waived the Company’s obligations to (1) comply with certain financial covenants relating to minimum revenue requirements through September 30, 2022, conditioned upon the satisfaction of certain conditions, including the Company raising additional capital and prepaying a portion of its outstanding debt by April 30, 2022 and (2) file financial statements along with its Annual Report on Form 10-K for the fiscal year ended December 31, 2021 that are not subject to any “going concern” qualification.

On March 13, 2022, the Company entered into a Securities Purchase Agreement (the “Purchase Agreement”) with a single healthcare-focused institutional investor (the “Purchaser”), pursuant to which the Company issued, in a registered direct offering (the “2022 Preferred Stock Offering”), 2,425 shares of Series A convertible preferred stock (the “Series A Preferred Stock”) and 2,425 shares of Series B convertible preferred stock (the “Series B Preferred Stock”) and Series A warrants (the “Series A Warrants”) to purchase up to an aggregate of 24,250,000 shares of the common stock of the Company (the “Common Stock”) and Series B warrants (the “Series B Warrants”) to purchase up to an aggregate of 24,250,000 shares of Common Stock. Each share of Series A Preferred Stock and Series B Preferred Stock has a stated value of $1,000 per share and a conversion price of $0.20 per share. The shares of preferred stock issued in the offering are convertible into an aggregate of 24,250,000 shares of Common Stock. The Series A Warrants have an exercise price of $0.26 per share, will become exercisable six months following the date of issuance, and will expire 5 years following the initial exercise date. The Series B Warrants have an exercise price of $0.26 per share, will become exercisable six months following the date of issuance, and will expire one and one-half years following the initial exercise date. The Purchase Agreement contains customary representations and warranties and agreements of the Company and the Purchaser and customary indemnification rights and obligations of the parties. Total gross proceeds from the 2022 Preferred Stock Offering, before deducting the placement agent's fees and other estimated offering expenses, are $4.9 million. The 2022 Preferred Stock Offering closed on March 14, 2022.