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Nature of Operations and Summary of Significant Accounting Policies - Additional Information (Detail) (USD $) | 3 Months Ended | 12 Months Ended
--- | --- | ---
Sep. 30, 2013 | Sep. 30, 2012 | Sep. 30, 2013 | Sep. 30, 2012
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items] |  |  |  |
Common stock equivalents included in Diluted earnings per share |  |  |  | 0
Weighted-average shares issuable upon the exercise of stock options, included in Diluted EPS |  |  | 84,000 |
Common Stock Equivalents |  |  | 2,000 |
Cash equivalents consist of short-term certificates of deposit maturities period |  |  | 3 months |
Net unrealized gains |  |  | $ 1,141,000 | $ 4,596,000
Estimated interest accrued |  |  | 399,000 | 545,000
Transfers of investments between Level 1 and Level 2 | 0 | 0 | 0 | 0
Impairment loss on property, equipments and intangible assets |  |  | 0 | 0
Time for the collection of cost associated with Pre- contract |  |  | 1 year |
Valuation allowance | 0 | 0 | 0 | 0
Three to Four Years Old Inventory [Member] |  |  |  |
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items] |  |  |  |
Cost basis reduction in inventory, percentage |  |  | 50.00% |
Three to Four Years Old Inventory [Member] | Minimum [Member] |  |  |  |
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items] |  |  |  |
Inventory, time period on the shelf, years |  |  | 3 years |
Three to Four Years Old Inventory [Member] | Maximum [Member] |  |  |  |
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items] |  |  |  |
Inventory, time period on the shelf, years |  |  | 4 years |
Four to Five Years Old Inventory [Member] |  |  |  |
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items] |  |  |  |
Cost basis reduction in inventory, percentage |  |  | 75.00% |
Four to Five Years Old Inventory [Member] | Minimum [Member] |  |  |  |
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items] |  |  |  |
Inventory, time period on the shelf, years |  |  | 4 years |
Four to Five Years Old Inventory [Member] | Maximum [Member] |  |  |  |
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items] |  |  |  |
Inventory, time period on the shelf, years |  |  | 5 years |
Greater Than Five Years Old Inventory [Member] |  |  |  |
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items] |  |  |  |
Inventory valuation estimate |  |  | $ 0 |
Greater Than Five Years Old Inventory [Member] | Minimum [Member] |  |  |  |
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items] |  |  |  |
Inventory, time period on the shelf, years |  |  | 5 years |
Stock Option [Member] |  |  |  |
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items] |  |  |  |
Weighted-average shares issuable upon the exercise of stock options, not included in Diluted EPS |  |  | 261,000 | 327,000
United States [Member] |  |  |  |
Nature Of Operations And Summary Of Significant Accounting Policies [Line Items] |  |  |  |
Percentage of net revenue from one or more separate U.S corporate entities on quarterly basis | 4.00% | 21.00% |  |
Percentage of net revenue from one or more separate U.S corporate entities on yearly basis |  |  | 11.00% | 26.00%

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