CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Revenues:
Royalties	$ 72	$ 68
Total revenues	72	68
Costs and expenses:
Research and development	3,279	2,706
Selling, general and administrative	2,235	1,486
Total operating expenses	5,514	4,192
Loss from operations	(5,442)	(4,124)
Interest income, net	57	36
Gain from change in fair value of derivative financial instruments—warrants	207	2
Other income (expense), net	(1)	(3)
Net loss	(5,179)	(4,089)
Preferred stock dividend payable on Series A Convertible Preferred Stock	(6)	(6)
Net loss attributable to common stockholders	$ (5,185)	$ (4,095)
Net loss per common share - basic and diluted (in dollars per share)	$ (0.14)	$ (0.41)
Weighted-average shares outstanding - basic and diluted (in shares)	37,164	9,910

The amount of net income or loss for the period per each share in instances when basic and diluted earnings per share are the same amount and reported as a single line item on the face of the financial statements. Basic earnings per share is the amount of net income or loss for the period per each share of common stock or unit outstanding during the reporting period. Diluted earnings per share includes the amount of net income or loss for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=121326447&loc=d3e1337-109256