Note 8 - Fair Value Measurements (Details Textual) $ in Thousands	Dec. 20, 2011	Jun. 30, 2022 USD ($)	Dec. 31, 2021 USD ($)
Debt Securities, Available-for-Sale, Amortized Cost, Total		$ 17,800
Debt Security Interest Rate Stated Percentage		7.50%
Debt Security, Available-For-Sale, Fair Value Discount Amount		$ 2,300	$ 2,300
Business Combination Contingent Consideration Arrangements, Payment To Option Holder Percentage Of Ebitda	1.00%
Business Combination, Contingent Consideration, Liability, Total		0	0
Business Combination, Contingent Consideration, Liability, Current			100
Prepaid Expenses and Other Current Assets [Member]
Debt Securities, Available-for-Sale, Current		700	600
Other Noncurrent Assets [Member]
Debt Securities, Available-for-Sale, Noncurrent		$ 13,400	$ 15,200
Measurement Input, Discount Rate [Member]
Debt Securities, Available-for-Sale, Measurement Input		0.116	0.101