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Stock-Based Compensation - Additional Information (Detail) $ in Millions | 1 Months Ended | 9 Months Ended |
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Jun. 30, 2025 shares | Jun. 30, 2024 shares | Jun. 30, 2023 shares | Jun. 30, 2022 shares | Jun. 30, 2021 shares | Jun. 30, 2020 shares | Jun. 30, 2019 shares | Sep. 30, 2025 USD ($) Period shares | Dec. 31, 2024 shares
Employee Stock Purchase Plan |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Stock-based compensation, option to be granted at percentage of fair value of common stock |  |  |  |  |  |  |  | 85.00% |
Employee Stock Purchase Plan, offering period |  |  |  |  |  |  |  | 12 months |
Number of purchase periods within each offering period | Period |  |  |  |  |  |  |  | 2 |
Increase in shares of common stock authorized for issuance |  | 2,000,000.0 |  |  |  | 1,500,000 |  |  |
Aggregate number of shares of common stock reserved for future issuance |  |  |  |  |  |  |  | 1,900,000 |
2008 Equity Incentive Plan |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Stock-based compensation, option to be granted at percentage of fair value of common stock |  |  |  |  |  |  |  | 100.00% |
Increase in shares of common stock authorized for issuance |  |  | 7,000,000 | 12,000,000 | 7,600,000 | 5,000,000 | 11,800,000 |  |
Stock-based compensation, award term |  |  |  |  |  |  |  | 10 years |
Performance-based stock options, outstanding |  |  |  |  |  |  |  | 3,200,000 |
Outstanding options and other stock based awards |  |  |  |  |  |  |  | 10,027,000 | 12,297,000
Number of additional awards granted |  |  |  |  |  |  |  | 0 |
2008 Equity Incentive Plan | Employee Stock Option |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Stock-based compensation, vesting period |  |  |  |  |  |  |  | 4 years |
2008 Equity Incentive Plan | Restricted Stock Units (RSUs) |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Number of unvested Restricted Stock Units |  |  |  |  |  |  |  | 17,768,000 | 13,661,000
2008 Equity Incentive Plan | Performance-based Stock Awards |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Employee Stock Purchase Plan, authorized shares for issuance |  |  |  |  |  |  |  | 500,000 |
2008 Equity Incentive Plan | Performance-based Cash Awards |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Stock option plan granted on cash award | $ |  |  |  |  |  |  |  | $ 1.0 |
2008 Equity Incentive Plan | Minimum | Restricted Stock Units (RSUs) |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Stock-based compensation, vesting period |  |  |  |  |  |  |  | 3 years |
2008 Equity Incentive Plan | Maximum | Restricted Stock Units (RSUs) |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Stock-based compensation, vesting period |  |  |  |  |  |  |  | 4 years |
2024 Equity Incentive Plan |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Stock-based compensation, option to be granted at percentage of fair value of common stock |  |  |  |  |  |  |  | 100.00% |
Increase in shares of common stock authorized for issuance | 10,000,000 |  |  |  |  |  |  |  |
Aggregate number of shares of common stock reserved for future issuance |  |  |  |  |  |  |  | 27,800,000 |
Stock-based compensation, award term |  |  |  |  |  |  |  | 10 years |
Number of shares available for future issuance |  |  |  |  |  |  |  | 14,900,000 |
Number of additional shares available for grant and issurance |  |  |  |  |  |  |  | 5,000,000 |
2024 Equity Incentive Plan | Employee Stock Option |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Stock-based compensation, vesting period |  |  |  |  |  |  |  | 4 years |
2024 Equity Incentive Plan | Minimum | Restricted Stock Units (RSUs) |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Stock-based compensation, vesting period |  |  |  |  |  |  |  | 2 years |
2024 Equity Incentive Plan | Maximum | Restricted Stock Units (RSUs) |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Stock-based compensation, vesting period |  |  |  |  |  |  |  | 4 years |
Amended 2008 Plan and 2024 Plan |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Outstanding options and other stock based awards |  |  |  |  |  |  |  | 10,000,000 |
Amended 2008 Plan and 2024 Plan | Restricted Stock Units (RSUs) |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Number of unvested Restricted Stock Units |  |  |  |  |  |  |  | 17,800,000 |

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