Note 10 - Commitments and Contingencies (Details Textual) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended		12 Months Ended
	May 31, 2020	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Apr. 30, 2019	Jun. 30, 2017
Operating Lease, Expense		$ 1,900	$ 1,400	$ 4,900	$ 4,100
Letters of Credit Outstanding, Amount		500		500		$ 500
Unrecorded Unconditional Purchase Obligation, Total		$ 10,193		10,193						$ 8,000
Payments for Unconditional Purchase Commitment						3,800	$ 5,500	$ 0
Microsoft Office 365 [Member]
Unrecorded Unconditional Purchase Obligation, Total									$ 2,100
Payments for Unconditional Purchase Commitment				700		700	$ 700
IT solutions [Member]
Unrecorded Unconditional Purchase Obligation, Total	$ 22,000
Payments for Unconditional Purchase Commitment				$ 8,700		$ 3,100
Unrecorded Unconditional Purchase Obligation, Term (Year)	3 years