Note 14 - Income Taxes - Effective Income Tax Rate (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Pretax income (loss)	$ (6,952)	$ (4,778)	$ 2,565	$ (2,651)	$ (22,376)	$ 3,400	$ 182	$ (1,511)	$ (11,816)	$ (20,305)	$ 32,531
(Provision) benefit for income taxes at federal statutory rate									2,481	4,264	(11,386)
Provisional rate adjustment - tax reform									0	148	(3,190)
State income taxes, net of federal benefit									781	1,396	(1,860)
Manufacturing deduction									0	0	958
Tax credits									1,238	346	0
Stock compensation									(389)	(12)	(44)
Non-deductible expenses related to Section 162(m)									(163)	0	0
Other									(133)	(67)	132
(Provision) benefit for income taxes									$ 3,815	$ 6,075	$ (15,390)
Effective tax rate									32.30%	29.90%	47.30%