| **Share-Based Compensation - Narrative (Detail) (USD $)**                          | 12 Months Ended | 3 Months Ended |
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| **Share-based Compensation Arrangement by Share-based Payment Award [Line Items]** |            |           |   |   |   |   |   |   |   |   |   |
| Stock option term                                                                  |            |           |   |   | 10 years |   |   |   |   |   |   |
| Stock options vesting percentage                                                   |            |           |   |   | 100.00% |   |   |   |   |   |   |
| Vested period                                                                      |            |           |   |   |   |   |   | 6 months | 2 years | 3 years |   |
| Percentage of average closing price to be paid by employees                        | 85.00%          |           |   |   |   |   |   |   |   |   |   |
| Common stock purchases through advance payroll deductions in a calendar year       |            |           |   | $ 25,000 |   |   |   |   |   |   |   |
| Share-based compensation                                                           | 1,773,000       | 1,492,000      | 1,315,000 |   |   |   |   |   |   |   |   |
| Estimated pre-vesting forfeiture rate                                              | 5.00%           |           |   |   | 4.73% | 4.77% | 5.00% |   |   |   |   |
| Unrecognized compensation expense                                                  |            |           |   |   | 36,000 |   |   |   |   | 2,665,000 | 0 |
| Unrecognized compensation expense expected recognition period                      |            |           |   |   | 0 years 4 months 22 days |   |   |   |   | 1 year 4 months 0 days |   |
| Weighted-average grant date fair value for stock options (in dollars per share)    | $ 5.73          | $ 3.97         | $ 3.09 |   |   |   |   |   |   |   |   |
| Aggregate intrinsic value of stock options exercised                               | 143,000         | 60,000         |   |   |   |   |   |   |   |   |   |
| Stock Options Exercised                                                            | 115,000         | 78,000         |   |   |   |   |   |   |   |   |   |
| Grant date fair value of ESPP options                                              |            |           |   |   |   |   |   |   |   |   | $ 16,000 |

| X                                                                                                                                                                                                                                                                                                                                                         |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The maximum amount allowed for advance payroll deductions in a calendar year for employee stock purchase plan.
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                                                                                         |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Share Based Compensation Arrangement by Share Based Payment Award Contractual Term Range
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                                                                                                                                   |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Share based Compensation Arrangement by Share based Payment Award, Fair Value Assumptions, Annual Forfeiture Rate
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                                                                                                           |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Share Based Compensation Arrangement By Share Based Payment Award Grant Date Fair Value Of Awards
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                                                                                |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Share Based Compensation Arrangement by Share based Payment Award, Vesting Percentage
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Share Based Compensation Arrangements By Share Based Payment Award Percentage Of Market Price At Eligible Employees Granted Options To Purchase Shares
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                            |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Unrecognized cost of unvested options awarded to employees as compensation.
+ References
No definition available.
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|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The cash inflow associated with the amount received from holders exercising their stock options. This item inherently excludes any excess tax benefit, which the entity may have realized and reported separately.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.
+ References
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| X                                                                                                                                                                                                      |
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.
+ References
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