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Summary of Significant Accounting Policies - Narrative (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Sep. 30, 2022 | Sep. 30, 2021 | Sep. 30, 2020
Revenue from External Customer [Line Items] |  |  |
Retention amounts included in accounts receivable | $ 6,900 | $ 9,600 |
Retained amount expected to be collected in the next twelve months | 6,000 |  |
Retained amount expected to be collected | 900 |  |
Research and development expenses | $ 6,963 | 6,670 | $ 6,265
Minimum |  |  |
Revenue from External Customer [Line Items] |  |  |
Long-term contract beginning | 1 month |  |
Accounts Receivable |  |  |
Revenue from External Customer [Line Items] |  |  |
Retention amounts included in accounts receivable | $ 6,900 | $ 9,600 |
Other Assets |  |  |
Revenue from External Customer [Line Items] |  |  |
Retained amount expected to be collected | $ 900 |  |

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