Note 10 - Net Loss Per Share Attributable to Common Stockholders (Tables)

12 Months Ended

Dec. 31, 2019

Notes Tables

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

	Year Ended
	December 31,
	2019			2018
Weighted average common shares outstanding:
Basic		109,057			106,564
Dilutive unvested stock, convertible preferred stock, Common Stock Warrants and IPO Warrants		—			—
Diluted		109,057			106,564
Basic and diluted net loss per share attributable to common stockholders	$	(0.45	)	$	(0.41	)

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

	Year Ended
	December 31,
	2019		2018
Unvested stock (1)		861		498
Convertible preferred stock		13,697		3,552
Common Stock Warrants		1,662		454
IPO Warrants (2)		12,082		12,082
Total potentially dilutive common shares		28,302		16,586