Note 13 - Selected Quarterly Financial Data (Unaudited) - Schedule of Quarterly Infomation (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended																12 Months Ended
		Dec. 31, 2018		Sep. 30, 2018		Jun. 30, 2018		Mar. 31, 2018		Dec. 31, 2017		Sep. 30, 2017		Jun. 30, 2017		Mar. 31, 2017		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenue		$ 44,187		$ 62,166		$ 65,278		$ 55,943		$ 24,019		$ 14,405		$ 11,074		$ 11,538		$ 227,574	$ 61,036	$ 5,216
Gross profit(a)	[1]	9,229		12,760		17,418		11,612		2,644		(2,120)		(701)		692
Operating income (loss)		2,025		5,804		10,647		5,620		(2,657)		(6,342)		(3,710)		(3,184)		24,096	(15,893)	(7,530)
Net income (loss)		$ 3,394		$ 6,211		$ 10,203		$ 5,266		$ (2,600)		$ (6,236)		$ (3,488)		$ (3,093)		$ 25,074	$ (15,417)	$ (7,515)
Basic (in dollars per share)		$ 0.08	[2]	$ 0.15	[2]	$ 0.25	[2]	$ 0.13	[2]	$ (0.07)	[2]	$ (0.16)	[2]	$ (0.09)	[2]	$ (0.10)	[2]	$ 0.63	$ (0.41)
Diluted (in dollars per share)		$ 0.08	[2]	$ 0.15	[2]	$ 0.25	[2]	$ 0.13	[2]	$ (0.07)	[2]	$ (0.16)	[2]	$ (0.09)	[2]	$ (0.10)	[2]	$ 0.62	$ (0.41)

[1] Represents total revenues less cost of sales (exclusive of items shown separately below)

[2] The sum of quarterly per share amounts may not equal amounts reported for the annual periods due to the effects of rounding.