Note 10 - Per Share Data - Reconciliation of the Basic and Diluted Loss Per Share (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Net income/(loss)	$ 20,890,158	$ (3,162,492)	$ 11,992,629	$ (1,532,715)
Less: Change in fair value of warrants	0	656,523	0	3,792,788
Net income/(loss), adjusted for change in fair value of warrants for diluted earnings per share	$ 20,890,158	$ (3,819,015)	$ 11,992,629	$ (5,325,503)
Weighted average shares outstanding: basic (in shares)	80,340,695	80,986,524	80,790,400	80,950,124
Effect of potential common shares (in shares)	176,168	1,128,137	169,412	1,179,477
Weighted average shares outstanding: diluted (in shares)	80,516,863	82,114,661	80,959,812	82,129,601
Basic income (loss) per share (in dollars per share)	$ 0.26	$ (0.04)	$ 0.15	$ (0.02)
Diluted income (loss) per share (in dollars per share)	$ 0.26	$ (0.05)	$ 0.15	$ (0.06)