Equity Incentive Plans

6 Months Ended

Jun. 30, 2023

Share-Based Payment Arrangement [Abstract]

Equity Incentive Plans

EQUITY INCENTIVE PLANS

Stock-Based Compensation

Stock-based compensation expense recognized for stock options, restricted stock units ("RSUs"), and our employee stock purchase program (the "ESPP") are recorded as operating expenses in our condensed statements of operations and comprehensive loss, as follows (in thousands):

	Three Months Ended June 30,				Six Months Ended June 30,
	2023		2022		2023		2022
Selling, general and administrative	$	2,303	$	2,220	$	4,391	$	4,728
Research and development	896		973		1,720		2,096
Total	$	3,199	$	3,193	$	6,111	$	6,824

As of June 30, 2023, our total unrecognized stock-based compensation expense, net of estimated forfeitures, and average remaining vesting period, included the following (dollars in thousands):

	Unrecognized Compensation Expense		Average Remaining Vesting Period (Years)
Stock option grants	$	21,167	3.0
RSU grants	$	7,776	3.1
ESPP	$	118	0.2

Stock Options

A summary of our stock option activity and related information for the six months ended June 30, 2023 is as follows (in thousands, except dollar amounts):

	Number of Shares	Weighted-Average Exercise Price per Share
Balance at December 31, 2022	13,963	$	4.83
Options granted	7,331	$	2.92
Options exercised	(99)	$	2.12
Options forfeited or canceled	(121)	$	4.87
Balance at June 30, 2023	21,074	$	4.18
Exercisable at June 30, 2023	10,269	$	5.63

Restricted Stock Units

A summary of our RSUs activity and related information for the six months ended June 30, 2023 is as follows (in thousands, except dollar amounts):

	Number of RSUs	Weighted-Average Grant Date Fair Value Per Share
Non-vested restricted stock units at December 31, 2022	1,406	$	2.17
Granted	2,203	$	2.98
Vested	(509)	$	2.86
Forfeited	(35)	$	3.88
Non-vested restricted stock units at June 30, 2023	3,065	$	2.62

Employee Stock Purchase Plan

During the six months ended June 30, 2023, we sold approximately 0.2 million shares of our common stock under the ESPP. The shares were purchased by employees at an average purchase price of $0.83 per share resulting in proceeds to us of approximately $0.1 million.

Issuance of Common Stock for Services

Under Our Amended and Restated Non-Employee Director Compensation Program, members of our board of directors may elect to receive shares of our stock in lieu of their cash fees. During the six months ended June 30, 2023, we issued 0.1 million shares of our common stock to members of the board of directors in accordance with the program.