Note 4 - Fair Value - Summary of Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands		Mar. 31, 2022	Dec. 31, 2021
Cash and cash equivalents	[1]	$ 24,828	$ 18,129
Restricted cash		1,176	1,154
Short-term investments		78,913	80,262
Long-term investments		14,727	37,435
Total assets measured at fair value		119,644	136,980
Contingent consideration		2,217	2,371
Total liabilities measured at fair value		2,217	2,371
Fair Value, Inputs, Level 1 [Member]
Cash and cash equivalents	[1]	24,828	18,129
Restricted cash		1,176	1,154
Short-term investments		0	0
Long-term investments		0	0
Total assets measured at fair value		26,004	19,283
Contingent consideration		0	0
Total liabilities measured at fair value		0	0
Fair Value, Inputs, Level 2 [Member]
Cash and cash equivalents	[1]	0	0
Restricted cash		0	0
Short-term investments		78,913	80,262
Long-term investments		14,727	37,435
Total assets measured at fair value		93,640	117,697
Contingent consideration		0	0
Total liabilities measured at fair value		0	0
Fair Value, Inputs, Level 3 [Member]
Cash and cash equivalents	[1]	0	0
Restricted cash		0	0
Short-term investments		0	0
Long-term investments		0	0
Total assets measured at fair value		0	0
Contingent consideration		2,217	2,371
Total liabilities measured at fair value		$ 2,217	$ 2,371

[1] Includes investments that are readily convertible to cash with original maturities of 90 days or less.