Stock-Based Compensation

6 Months Ended

Jun. 30, 2021

Share-based Payment Arrangement [Abstract]

Stock-Based CompensationStock-based compensation expense has been reported in the Company’s condensed statements of operations for the three and six months ended June 30, 2021 and 2020 as follows (in thousands):


	Three Months Ended June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
General and administrative	$	510	$	402	$	984	$	742
Research and development	219		173		414		304
Total stock-based compensation	$	729	$	575	$	1,398	$	1,046

As of June 30, 2021, the total unrecognized compensation expense related to unvested employee and non-employee stock options was $5.6 million, which is expected to be recognized over a weighted-average period of approximately 2.5 years.

In October 2018, the Company's board of directors and stockholders approved the ESPP, which became effective on October 17, 2018. The ESPP is intended to qualify as an "employee stock purchase plan" within the meaning of Section 423 of the Internal Revenue Code.

Under the ESPP, eligible employees are granted rights to purchase shares of common stock, which are funded through payroll deductions that cannot exceed 15% of each employee’s compensation. The ESPP generally provides for a 24-month offering period, which includes four six-month purchase periods. At the end of each purchase period, eligible employees are permitted to purchase shares of common stock at 85% of the lower of fair market value at the beginning of the offering period or fair market value at the end of the purchase period. The ESPP is considered a compensatory plan, and the Company recorded stock-based compensation expense of $0.1 million and $21,000 for the three months ended June 30, 2021 and 2020, respectively, and $0.1 million and $21,000 for the six months ended June 30, 2021 and 2020, respectively. The Company issued 72,105 and zero shares of common stock under the ESPP for the six months ended June 30, 2021 and 2020, respectively.

As of June 30, 2021, the total unrecognized compensation expense related to the ESPP was $0.2 million, which is expected to be recognized over a weighted-average period of approximately 0.8 years.