Common Stock and Preferred Stock (Tables)

9 Months Ended

Sep. 30, 2021

Earnings Per Share [Abstract]

Schedule of basic and diluted net loss per share

Basic and diluted net loss per common share (in thousands, except per share amounts) was as follows:

	Three Months Ended September 30,				Nine Months Ended September 30,
	2021		2020		2021		2020
Net loss	$	(7,883)	$	(5,673)	$	(17,093)	$	(19,481)
Dividends on preferred stock - declared and undeclared	(2,239)		(464)		(6,716)		(464)
Net loss attributable to common stockholders	$	(10,122)	$	(6,137)	$	(23,809)	$	(19,945)
Weighted-average shares of common stock outstanding	18,915		17,280		18,236		16,990
Net loss per common share - basic and diluted	$	(0.54)	$	(0.36)	$	(1.31)	$	(1.17)

Schedule of shares excluded from net loss per share

The following common equivalent shares as of September 30, 2021 and 2020, issuable upon exercise of stock options and warrants, have been excluded from the diluted earnings per share calculation as their effect was anti-dilutive:

	September 30,
	2021	2020
Warrants to purchase common stock	49,803	1,465,927
Options to purchase common stock	3,486,750	3,524,625
Total	3,536,553	4,990,552