Note 5 - Fair Value Measurements - Financial Assets and Liabilities, Fair Value (Details) - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
Assets, fair value	$ 362,450	$ 248,482
Fair Value, Inputs, Level 1 [Member]
Assets, fair value	205,158	77,204
Fair Value, Inputs, Level 2 [Member]
Assets, fair value	157,243	171,130
Fair Value, Inputs, Level 3 [Member]
Assets, fair value	49	148
Money Market Funds [Member]
Available for sale securities, fair value	129,674	11,867
Money Market Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Available for sale securities, fair value	129,674	11,867
Money Market Funds [Member] | Fair Value, Inputs, Level 2 [Member]
Available for sale securities, fair value	0	0
Money Market Funds [Member] | Fair Value, Inputs, Level 3 [Member]
Available for sale securities, fair value	0	0
Certificates of Deposit [Member]
Available for sale securities, fair value	157,243	164,418
Certificates of Deposit [Member] | Fair Value, Inputs, Level 1 [Member]
Available for sale securities, fair value	0	0
Certificates of Deposit [Member] | Fair Value, Inputs, Level 2 [Member]
Available for sale securities, fair value	157,243	164,418
Certificates of Deposit [Member] | Fair Value, Inputs, Level 3 [Member]
Available for sale securities, fair value	0	0
Auction Rate Securities [Member]
Available for sale securities, fair value	49	148
Auction Rate Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Available for sale securities, fair value	0	0
Auction Rate Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Available for sale securities, fair value	0	0
Auction Rate Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Available for sale securities, fair value	49	148
Corporate Debt Securities [Member]
Available for sale securities, fair value		6,712
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Available for sale securities, fair value		0
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Available for sale securities, fair value		6,712
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Available for sale securities, fair value		0
Mutual Fund [Member]
Available for sale securities, fair value	75,484	65,337
Mutual Fund [Member] | Fair Value, Inputs, Level 1 [Member]
Available for sale securities, fair value	75,484	65,337
Mutual Fund [Member] | Fair Value, Inputs, Level 2 [Member]
Available for sale securities, fair value	0	0
Mutual Fund [Member] | Fair Value, Inputs, Level 3 [Member]
Available for sale securities, fair value	$ 0	$ 0