Note 9 - Fair Value Measurement (Tables)

3 Months Ended

Mar. 31, 2021

Notes Tables

Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]

	Fair Value Measurement at Reporting Date Using
March 31, 2021	Level 1		Level 2		Level 3		Total
Cash equivalents
Money market funds	$	42,488	$	—	$	—	$	42,488
Other current assets
Commodity swap		—		1,106		—		1,106
Other noncurrent assets
Restricted cash		1,512		—		—		1,512
Total assets	$	44,000	$	1,106	$	—	$	45,106
Accrued and other current liabilities
Interest rate swap	$	—	$	6,535	$	—	$	6,535
Total liabilities	$	—	$	6,535	$	—	$	6,535

December 31, 2020
Cash equivalents
Money market funds	$	70,483	$	—	$	—	$	70,483
Other noncurrent assets
Restricted cash		1,512		—		—		1,512
Total assets	$	71,995	$	—	$	—	$	71,995
Accrued and other current liabilities
Interest rate swap	$	—	$	7,606	$	—	$	7,606
Total liabilities	$	—	$	7,606	$	—	$	7,606

March 31, 2020
Cash equivalents
Money market funds	$	58,693	$	—	$	—	$	58,693
Other noncurrent assets
Restricted cash		4,881		—		—		4,881
Total assets	$	63,574	$	—	$	—	$	63,574
Accrued and other current liabilities
Interest rate swap	$	—	$	8,890	$	—	$	8,890
Total liabilities	$	—	$	8,890	$	—	$	8,890

Fair Value, by Balance Sheet Grouping [Table Text Block]

		March 31, 2021				December 31, 2020				March 31, 2020
(in thousands)	Fair Value Hierarchy	Carrying Value		Fair Value		Carrying Value		Fair Value		Carrying Value		Fair Value
Assets:
Held-to-maturity marketable securities (1)	Level 1	$	11,300	$	11,258	$	5,200	$	5,200	$	5,000	$	5,006
Liabilities (including current maturities):
2.75% Convertible Notes (2),(3)	Level 2	$	202,018	$	324,013	$	200,303	$	248,400	$	195,295	$	176,094
Credit Agreement - term loan (2)	Level 3		129,375		130,645		131,250		133,030		136,875		137,194
Credit Agreement - revolving credit facility (2)	Level 3		—		—		—		—		25,000		25,061