Note 3 - Marketable Securities - Investment in Marketable Securities (Details) $ in Thousands	Dec. 31, 2021 USD ($)
Amortized cost	$ 46,799
Gross unrealized gains	0
Gross unrealized losses	(40)
Fair value	47,029
Corporate Debt Securities [Member]
Amortized cost	32,302
Gross unrealized gains	0
Gross unrealized losses	(36)
Fair value	32,529
Commercial Paper [Member]
Amortized cost	8,891
Gross unrealized gains	0
Gross unrealized losses	0
Fair value	8,891
Money Market Funds [Member]
Amortized cost	3,686
Gross unrealized gains	0
Gross unrealized losses	0
Fair value	3,686
Debt Security, Corporate, Non-US [Member]
Amortized cost	1,920
Gross unrealized gains	0
Gross unrealized losses	(4)
Fair value	$ 1,923

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), including amounts presented in cash and cash equivalents.

No definition available.

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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).

+ References

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-Publisher FASB
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-Topic 320
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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).

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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
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-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=124258926&loc=SL82898722-210454

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