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Concentrations of credit risk and major customers (Details)
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12 Months Ended | ||
|---|---|---|---|
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Sep. 30, 2013
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Sep. 30, 2012
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Sep. 30, 2011
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| Revenue Recognition | |||
| Number of major customers | 3 | ||
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Total Revenue | Foreign customers
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| Revenue Recognition | |||
| Revenue from major customers (as a percent) | 25.00% | 26.00% | 32.00% |
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Total Revenue | State government agencies
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| Revenue Recognition | |||
| Revenue from major customers (as a percent) | 56.00% | ||
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Total Revenue | Foreign government agencies
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| Revenue Recognition | |||
| Revenue from major customers (as a percent) | 24.00% | ||
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Total Revenue | U.S.-based federal government agencies
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| Revenue Recognition | |||
| Revenue from major customers (as a percent) | 12.00% | ||
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Total Revenue | Other sources including local municipalities and commercial customers
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| Revenue Recognition | |||
| Revenue from major customers (as a percent) | 8.00% | ||
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Total Revenue | State of Texas
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|||
| Revenue Recognition | |||
| Revenue from major customers (as a percent) | 14.00% | 18.00% | 16.00% |
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Total Revenue | Commonwealth of Australia
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| Revenue Recognition | |||
| Revenue from major customers (as a percent) | 12.00% | 16.00% | 19.00% |
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Total Revenue | United States Federal
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| Revenue Recognition | |||
| Revenue from major customers (as a percent) | 12.00% | 10.00% | |
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Total Revenue | United States Federal | Maximum
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|||
| Revenue Recognition | |||
| Revenue from major customers (as a percent) | 10.00% | ||
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Total Revenue | State of California
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| Revenue Recognition | |||
| Revenue from major customers (as a percent) | 10.00% | 11.00% | |