Note 3 - Basis of Presentation and Summary of Significant Accounting Policies (Tables)

6 Months Ended

Jun. 30, 2018

Notes Tables

Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]

	Three Months Ended June 30,						Six Months Ended June 30,
	2018			2017			2018			2017
Basic net (loss) income per common share calculation:
Net (loss) income	$	(2,765,181	)	$	20,387,741		$	(6,079,142	)	$	(8,251,037	)
Accretion of Series A cumulative preferred dividends		—			(487,460	)		(85,993	)		(546,305	)
Undistributed earnings allocated to participating securities		—			(10,416,153	)
Deemed dividend related to the make-whole provision for the conversion of Series A preferred stock into common		—			—			(8,167,895	)		—
Net (loss) income attributable to common		(2,765,181	)		9,484,128			(14,333,030	)		(8,797,342	)
Weighted average common shares outstanding, basic		50,546,021			10,828,063			46,357,478			10,582,521
Net (loss) income per share of common, basic	$	(0.05	)	$	0.88		$	(0.31	)	$	(0.83	)
Diluted net income (loss) per common share calculation:
Net income (loss) attributable to common		(2,765,181	)		9,484,128			(14,333,030	)		(8,797,342	)
Add change in fair value of warrant liability		—			(23,387,850	)		—			(10,468,176	)
Diluted net loss		(2,765,181	)		(13,903,722	)		(14,333,030	)		(19,265,518	)
Weighted average common shares outstanding, basic		50,546,021			10,828,063			46,357,478			10,582,521
Add shares from dilutive warrants		—			3,044,569			—			1,756,865
Common stock equivalents		50,546,021			13,872,632			46,357,478			12,339,386
Diluted net loss per share of common	$	(0.05	)	$	(1.00	)	$	(0.31	)	$	(1.56	)

Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]

	June 30,
	2018		2017
Convertible debt		—		774,886
Convertible preferred stock		—		10,449,338
Common stock warrants		31,312,512		457,721
Stock options		3,213,797		2,525,989
Unvested restricted stock awards		—		6,132
		34,526,309		14,214,066