Note 4 - Fair Value Measurement - Estimated Fair Value of Marketable Securities and Gross Unrealized Holding Gains and Losses (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
cash equivalents, amortized cost	$ 12,730	$ 14,802	$ 23,443
Cash equivalents unrealized gains	0	0	0
cash equivalents, unrealized loss	0	0	0
fair value	12,730	14,802	23,443
marketable securities, amortization cost		1,997	12,921
Unrealized gains, securities		0	0
Unrealized loss, securities		0	(4)
Marketable Securities, fair value		1,997	12,917
US Treasury Securities [Member]
marketable securities, amortization cost		1,997
Unrealized gains, securities		0
Unrealized loss, securities		0
Marketable Securities, fair value		1,997
Commercial Paper, Not Included with Cash and Cash Equivalents [Member]
marketable securities, amortization cost			5,498
Unrealized gains, securities			0
Unrealized loss, securities			0
Marketable Securities, fair value			5,498
Corporate Debt Securities [Member]
marketable securities, amortization cost			4,515
Unrealized gains, securities			0
Unrealized loss, securities			(3)
Marketable Securities, fair value			4,512
US Government Debt Securities [Member]
marketable securities, amortization cost			1,503
Unrealized gains, securities			0
Unrealized loss, securities			0
Marketable Securities, fair value			1,503
Asset-Backed Securities [Member]
marketable securities, amortization cost			1,405
Unrealized gains, securities			0
Unrealized loss, securities			(1)
Marketable Securities, fair value			1,404
Cash [Member]
cash equivalents, amortized cost	3,181	131	4,917
Cash equivalents unrealized gains	0	0	0
cash equivalents, unrealized loss	0	0	0
fair value	3,181	131	4,917
Money Market Funds [Member]
cash equivalents, amortized cost	9,549	14,671	18,526
Cash equivalents unrealized gains	0	0	0
cash equivalents, unrealized loss	0	0	0
fair value	$ 9,549	$ 14,671	$ 18,526

Represents accumulated gross unrealized gain of cash and cash equivalents.

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The amount of unrealized loss from cash and cash equivalents.

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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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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).

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Amount of 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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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Amount of short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

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