Note 12 - Convertible Senior Notes (Tables)

3 Months Ended

Mar. 31, 2022

Notes Tables

Convertible Debt [Table Text Block]

	March 31,			December 31,
	2022			2021
Principal	$	80,500		$	80,500
Unamortized debt issuance costs		(1,616	)		(1,820	)
Net carrying amount	$	78,884		$	78,680

Interest Income and Interest Expense Disclosure [Table Text Block]

	Three months ended March 31,
	2022			2021
Contractual interest expense	$	1,006		$	1,006
Amortization of debt issuance costs		204			204
Total interest cost	$	1,210		$	1,210
Effective interest rate		5.1	%		5.1	%