Note 4 - Investments - Schedule of Carrying Value and Fair Value of Securities Available-for-sale (Details) - USD ($) $ in Thousands |
Apr. 30, 2026 |
Apr. 30, 2025 |
|---|---|---|
| Due within 1 year, amortized cost | $ 31,770 | $ 15,407 |
| Due within 1 year, gross unrealized gains | 3 | 10 |
| Due within 1 year, gross unrealized losses | (44) | (1) |
| Due within 1 year, fair value | 31,729 | 15,416 |
| Due within 1 year through 5 years, amortized cost | 5,044 | 7,111 |
| Due within 1 year through 5 years, gross unrealized gains | 0 | 0 |
| Due within 1 year through 5 years, gross unrealized losses | (90) | (92) |
| Due within 1 year through 5 years, fair value | 4,954 | 7,019 |
| Total investment in government debt securities, amortized cost | 36,814 | 22,518 |
| Total investment in government debt securities, gross unrealized gains | 3 | 10 |
| Total investment in government debt securities, gross unrealized losses | (134) | (93) |
| Total investment in government debt securities, fair value | $ 36,683 | $ 22,435 |
| X | ||||||||||
- Definition Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- Definition Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- Definition Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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| X | ||||||||||
- Definition Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in second through fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach). Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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| X | ||||||||||
- Definition Fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in second through fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach). Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- Definition Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach). Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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| X | ||||||||||
- Definition Fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach). Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- Definition Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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| X | ||||||||||
- Definition Accumulated gross unrealized losses of available-for-sale debt securities maturing in the next five fiscal years following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. No definition available.
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| X | ||||||||||
- Definition Accumulated gross unrealized gains available-for-sale debt securities maturing in the next five fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. No definition available.
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| X | ||||||||||
- Definition Accumulated gross unrealized gains available-for-sale debt securities maturing in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. No definition available.
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| X | ||||||||||
- Definition Accumulated gross unrealized losses of available-for-sale debt securities maturing in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. No definition available.
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