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Stock Incentive Plans and Stock-Based Compensation - Additional Information (Detail) | 6 Months Ended | 12 Months Ended |  |
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Nov. 30, 2024 $ / shares shares | May 31, 2024 $ / shares shares | Nov. 30, 2023 $ / shares shares | May 31, 2023 $ / shares shares | Nov. 30, 2022 $ / shares shares | May 31, 2022 $ / shares shares | Dec. 31, 2024 USD ($) $ / shares shares | Dec. 31, 2023 USD ($) $ / shares | Dec. 31, 2022 USD ($) $ / shares | Dec. 31, 2024 £ / shares | Dec. 31, 2024 USD ($) shares | Dec. 31, 2023 £ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Common stock, par value | £ / shares |  |  |  |  |  |  |  |  |  | £ 0.50 |  | £ 0.50
Granted | shares |  |  |  |  |  |  | 9,100,000 |  |  |  |  |
Weighted average fair value of the stock options granted | $ / shares |  |  |  |  |  |  | $ 0.57 | $ 1.27 | $ 2.56 |  |  |
Grant date fair value of options vested |  |  |  |  |  |  | $ 7,300,000 | $ 8,200,000 | $ 16,600,000 |  |  |
Proceeds from the exercise of options |  |  |  |  |  |  | $ 10,000 | 1,882,000 | 60,000 |  |  |
Intrinsic value of options exercised |  |  |  |  |  |  |  | 400,000 |  |  |  |
Unrecognized stock-based compensation expense related to stock option |  |  |  |  |  |  |  |  |  |  | $ 6,200,000 |
Unrecognized stock-based compensation expense related to stock option, recognition period |  |  |  |  |  |  | 3 years 2 months 12 days |  |  |  |  |
Compensation expense related to stock option |  |  |  |  |  |  | $ 7,300,000 | 6,800,000 | 14,800,000 |  |  |
Compensation expense in relation to restricted stock units |  |  |  |  |  |  | 10,400,000 | 9,800,000 | 11,400,000 |  |  |
Total grant date fair value of restricted stock units vested |  |  |  |  |  |  | 9,300,000 | $ 16,300,000 | 14,300,000 |  |  |
Ordinary shares, reserved and available for issuance | shares |  |  |  |  |  |  |  |  |  |  | 27,290,000 |
Maximum |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Proceeds from the exercise of options |  |  |  |  |  |  | 100,000 |  |  |  |  |
Intrinsic value of options exercised |  |  |  |  |  |  | $ 100,000 |  | $ 100,000 |  |  |
Stock Options |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Employee Stock options, Vesting Period |  |  |  |  |  |  | 4 years |  |  |  |  |
Restricted Stock Units (RSUs) |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Unrecognized stock-based compensation expense related to stock option |  |  |  |  |  |  |  |  |  |  | $ 10,100,000 |
Unrecognized stock-based compensation expense related to stock option, recognition period |  |  |  |  |  |  | 1 year 8 months 12 days |  |  |  |  |
Market-Based Stock Option Award |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Granted | shares |  |  |  |  |  |  | 5,000,000 |  |  |  |  |
Weighted average fair value of the stock options granted | $ / shares |  |  |  |  |  |  | $ 0.29 |  |  |  |  |
Stock Incentive Plan 2020 |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Number of shares | shares |  |  |  |  |  |  |  |  |  |  | 20,000,000 |
Plans | Stock Options |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Employee Stock options, Vesting Period |  |  |  |  |  |  | 4 years |  |  |  |  |
Expire period |  |  |  |  |  |  | 10 years |  |  |  |  |
2017 Employee Stock Purchase Plan |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Ordinary shares, reserved and available for issuance | shares |  |  |  |  |  |  |  |  |  |  | 3,000,000 |
Percentage of fair market value to payroll deductions to eligible employees to purchase ordinary shares |  |  |  |  |  |  | 85.00% |  |  |  |  |
Maximum fair market value of stock which can be purchased by participant in calendar year |  |  |  |  |  |  | $ 25,000 |  |  |  |  |
Issuance of common stock under employee stock purchase plan (in shares) | shares | 116,766 | 139,982 | 113,749 | 205,861 | 191,482 | 265,214 |  |  |  |  |  |
Sale of stock price per share | $ / shares | $ 0.43 | $ 0.64 | $ 0.66 | $ 1.01 | $ 1.15 | $ 1.45 |  |  |  |  |  |
Reserved for future issuance | shares |  |  |  |  |  |  |  |  |  |  | 785,219 |
2017 Employee Stock Purchase Plan | Maximum |  |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Percentage of payroll deductions to eligible employees to purchase ordinary shares |  |  |  |  |  |  |  |  |  |  | 15.00% |

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