Convertible Preference Shares	12 Months Ended
Dec. 31, 2021
Temporary Equity Disclosure [Abstract]
Convertible Preference Shares	8. Convertible Preference Shares As of December 31, 2021 we had no preference shares authorized, issued and outstanding. As of December 31, 2020, we had 584,583 class B preference shares authorized, issued and outstanding. Sales and Issuances of Preference Shares During the Years Ended December 31, 2021 and 2020 In April 2020, we issued 142,437 class B preference shares at a subscription price of $64.48 per share to existing related-party investors upon the conversion of convertible notes (Note 3). We recorded the 142,437 class B preference shares at fair value of $10.3 million ($72.15 per share) determined using an option pricing model, or OPM, assuming a Company equity value of $40.6 million, a term of 1.6 years, volatility of 86.0% and a risk-free rate of 0.18%. We incurred issuance costs of $4,000 in connection with the issuances of the class B preference shares on conversion of the convertible notes. In July 2020, we issued 75,845 class B preference shares to existing related-party investors at a subscription price of $67.46 per share for gross cash proceeds of $5.1 million. We recorded the 75,845 class B preference shares at fair value of $5.6 million ($73.60 per share), resulting in a deemed dividend of $0.5 million recorded against additional paid-in capital on our balance sheet. Fair value of the class B preference shares issued on this date was determined using an OPM methodology assuming a Company equity value of $47.6 million, a term of 1.36 years, volatility of 92.4% and a risk-free rate of 0.16%. We incurred issuance costs of $10,000 in connection with the issuances of the class B preference shares. In January 2021, we completed an investment agreement, Class C Investment Agreement, for the sale and issuance of up to 1,263,804 class C preference shares to new investors and existing related-party investors at a subscription price of $121.55 per share. Then, pursuant to the Class C Investment Agreement, we issued 505,520 class C preference shares for gross cash proceeds of $61.5 million. The Class C Investment Agreement further provided for a milestone closing in the event of certain development milestones before April 2022, whereby purchasers of class C preference shares are obligated to a further subscription amount of $88.4 million, or the Preference Shares Tranche Obligation, which resulted in a further issuance of 689,344 class C preference shares at a subscription price of $128.19 per share. We incurred issuance costs of $340,000 in connection with the issuances of the class C preference shares. We concluded that the Preference Shares Tranche Obligation met the definition of a freestanding financial instrument, as it was legally detachable and separately exercisable from the class C preference shares. Therefore, we allocated the proceeds received from the issuance of shares under the Class C Investment Agreement between the Preference Shares Tranche Obligation and the class C preference shares. The fair value of the Preference Shares Tranche Obligation of $2.4 million on issuance was allocated from the $61.5 million proceeds of the class C preference shares financing and was classified as a current liability on the balance sheet as the class C preference shares would become redeemable upon a Deemed Liquidation Event, the occurrence of which is not within our control. In March 2021, prior to a milestone closing, an investor elected to purchase and we issued 35,825 class C preference shares for gross cash proceeds of $4.2 million pursuant to the Class C Investment Agreement. As a result of entering into a collaboration agreement with Merck in September 2021, the number of class C preference shares issued in March 2021 was adjusted downward to 32,568 class C preference shares. In October 2021, investors purchased and we issued 656,776 class C preference shares for gross cash proceeds of $84.1 million pursuant to the Class C Investment Agreement, resulting in the settlement of the preference shares tranche obligations. Immediately prior to consummation of our IPO, all outstanding class B and class C preference shares were converted into 20,415,213 shares of common stock.

Convertible Preference Shares

12 Months Ended

Dec. 31, 2021

Temporary Equity Disclosure [Abstract]

8. Convertible Preference Shares

As of December 31, 2021 we had no preference shares authorized, issued and outstanding. As of December 31, 2020, we had 584,583 class B preference shares authorized, issued and outstanding.

Sales and Issuances of Preference Shares During the Years Ended December 31, 2021 and 2020

In April 2020, we issued 142,437 class B preference shares at a subscription price of $64.48 per share to existing related-party investors upon the conversion of convertible notes (Note 3). We recorded the 142,437 class B preference shares at fair value of $10.3 million ($72.15 per share) determined using an option pricing model, or OPM, assuming a Company equity value of $40.6 million, a term of 1.6 years, volatility of 86.0% and a risk-free rate of 0.18%. We incurred issuance costs of $4,000 in connection with the issuances of the class B preference shares on conversion of the convertible notes.

In July 2020, we issued 75,845 class B preference shares to existing related-party investors at a subscription price of $67.46 per share for gross cash proceeds of $5.1 million. We recorded the 75,845 class B preference shares at fair value of $5.6 million ($73.60 per share), resulting in a deemed dividend of $0.5 million recorded against additional paid-in capital on our balance sheet. Fair value of the class B preference shares issued on this date was determined using an OPM methodology assuming a Company equity value of $47.6 million, a term of 1.36 years, volatility of 92.4% and a risk-free rate of 0.16%. We incurred issuance costs of $10,000 in connection with the issuances of the class B preference shares.

In January 2021, we completed an investment agreement, Class C Investment Agreement, for the sale and issuance of up to 1,263,804 class C preference shares to new investors and existing related-party investors at a subscription price of $121.55 per share. Then, pursuant to the Class C Investment Agreement, we issued 505,520 class C preference shares for gross cash proceeds of $61.5 million. The Class C Investment Agreement further provided for a milestone closing in the event of certain development milestones before April 2022, whereby purchasers of class C preference shares are obligated to a further subscription amount of $88.4 million, or the Preference Shares Tranche Obligation, which resulted in a further issuance of 689,344 class C preference shares at a subscription price of $128.19 per share. We incurred issuance costs of $340,000 in connection with the issuances of the class C preference shares.

We concluded that the Preference Shares Tranche Obligation met the definition of a freestanding financial instrument, as it was legally detachable and separately exercisable from the class C preference shares. Therefore, we allocated the proceeds received from the issuance of shares under the Class C Investment Agreement between the Preference Shares Tranche Obligation and the class C preference shares. The fair value of the Preference Shares Tranche Obligation of $2.4 million on issuance was allocated from the $61.5 million proceeds of the class C preference shares financing and was classified as a current liability on the balance sheet as the class C preference shares would become redeemable upon a Deemed Liquidation Event, the occurrence of which is not within our control.

In March 2021, prior to a milestone closing, an investor elected to purchase and we issued 35,825 class C preference shares for gross cash proceeds of $4.2 million pursuant to the Class C Investment Agreement. As a result of entering into a collaboration agreement with Merck in September 2021, the number of class C preference shares issued in March 2021 was adjusted downward to 32,568 class C preference shares. In October 2021, investors purchased and we issued 656,776 class C preference shares for gross cash proceeds of $84.1 million pursuant to the Class C Investment Agreement, resulting in the settlement of the preference shares tranche obligations.

Immediately prior to consummation of our IPO, all outstanding class B and class C preference shares were converted into 20,415,213 shares of common stock.