Note 4 - Financial Statement Details - Accounts Payable and Accrued Expenses (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
CERTS Grant	$ 16,677	$ 0
Accrued other expense	10,150	5,645
Accounts payable	8,778	5,285
Bonus compensation liability	4,193	2,963
Employee liability	4,115	3,495
Refunds and commissions payable	2,209	1,803
Travel certificate liability	870	870
Royalty payable	818	0
Accrued travel insurance expense	505	270
Income tax liabilities	2	2
Foreign currency forward contract liability	0	2,008
Total accounts payable and accrued expenses	$ 48,317	$ 22,341