Annual report pursuant to Section 13 and 15(d)

CONSOLIDATED STATEMENTS OF CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY

CONSOLIDATED STATEMENTS OF CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Warrants Related To debt arrangement	At The Market	Private Placement Pre-Funded Warrant	Follow On Offering	Follow On Offering Common Stock and Warrants	Follow On Offering Preferred Stock and Warrants	Common Stock	Common Stock At The Market	Common Stock Private Placement Pre-Funded Warrant	Common Stock Follow On Offering	Common Stock Follow On Offering Common Stock and Warrants	Series A Convertible Preferred Stock	Series A Convertible Preferred Stock Follow On Offering Preferred Stock and Warrants	Additional Paid-In Capital	Additional Paid-In Capital Warrants Related To debt arrangement	Additional Paid-In Capital At The Market	Additional Paid-In Capital Private Placement Pre-Funded Warrant	Additional Paid-In Capital Follow On Offering	Additional Paid-In Capital Follow On Offering Common Stock and Warrants	Additional Paid-In Capital Follow On Offering Preferred Stock and Warrants	Accumulated Other Comprehensive (Loss) Gain	Accumulated Deficit
Balance at Dec. 31, 2018	$ 78,586							$ 34							$ 296,100							$ (3)	$ (217,545)
Balance (in shares) at Dec. 31, 2018								33,765,864
Exercise of stock options	211														211
Exercise of stock options, Shares								60,181
Issuance of common stock / preferred stock, warrants, net of issuance costs			$ 799			$ 60,359	$ 4,638					$ 9					$ 799			$ 60,350	$ 4,638
Issuance of common stock / preferred stock, warrants, net of issuance costs (in shares)									180,787			8,667,333		666
Conversion of preferred stock, Shares								666,000					(666)
Issuance of shares under Employee Stock Purchase Plan	161														161
Issuance of shares under Employee Stock Purchase Plan, Shares								27,386
Exercise of warrants	2														2
Exercise of warrants, Shares								250
Stock-based compensation expense	9,839														9,839
Other comprehensive gain (loss)	27																					27
Net loss	(75,438)																						(75,438)
Balance at Dec. 31, 2019	79,184							$ 43							372,100							24	(292,983)
Balance (in shares) at Dec. 31, 2019								43,367,801
Exercise of stock options	1,076														1,076
Exercise of stock options, Shares								170,723
Vesting of restricted stock units								109,362
Issuance of common stock / preferred stock, warrants, net of issuance costs		$ 302	$ 11,919	$ 70,753					$ 2	$ 11						$ 302	$ 11,917	$ 70,742
Issuance of common stock / preferred stock, warrants, net of issuance costs (in shares)									2,201,810	10,312,500
Issuance of shares under Employee Stock Purchase Plan	433														433
Issuance of shares under Employee Stock Purchase Plan, Shares								59,550
Exercise of warrants	9														9
Exercise of warrants, Shares								1,000
Stock-based compensation expense	10,939														10,939
Other comprehensive gain (loss)	(24)																					(24)
Net loss	(84,038)																						(84,038)
Balance at Dec. 31, 2020	$ 90,553							$ 56							467,518								(377,021)
Balance (in shares) at Dec. 31, 2020	56,222,746							56,222,746
Exercise of stock options	$ 157														157
Exercise of stock options, Shares	20,134							20,134
Vesting of restricted stock units								286,837
Issuance of common stock / preferred stock, warrants, net of issuance costs					$ 70,468						$ 5								$ 70,463
Issuance of common stock / preferred stock, warrants, net of issuance costs (in shares)											5,400,000
Issuance of shares under Employee Stock Purchase Plan	$ 323														323
Issuance of shares under Employee Stock Purchase Plan, Shares								94,318
Stock-based compensation expense	10,354														10,354
Other comprehensive gain (loss)	(79)																					(79)
Net loss	(86,558)																						(86,558)
Balance at Dec. 31, 2021	$ 85,218							$ 61							$ 548,815							$ (79)	$ (463,579)
Balance (in shares) at Dec. 31, 2021	62,024,035							62,024,035