Presented below is a summary of the number of shares authorized, outstanding, and available for future grants under each of the Company’s stock option plans as of March 31, 2022 (in thousands):

The following table sets forth a summary of the activity under all of the Company’s stock option plans for the nine months ended March 31, 2022 (shares in thousands):

(1)	Represents the weighted average exercise price.

(2)	Represents the weighted average remaining contractual term for the number of years until the stock options expire.

For the nine months ended March 31, 2022, the aggregate fair value of stock options granted for approximately 0.4 million shares of common stock that provide solely for time-based vesting, amounted to $1.7 million or approximately $4.09 per share as of the grant dates. Fair value was computed using the BSM option-pricing model and will result in the recognition of compensation cost ratably over the expected vesting period of the stock options. For the nine months ended March 31, 2022, the fair value of stock options was estimated on the date of grant, with the following weighted-average assumptions:


Market price of common stock on grant date	$	4.09
Expected volatility		94	%
Risk free interest rate		1.8	%
Expected term (years)		6.1
Dividend yield		0	%

Share-based compensation expense for the three and nine months ended March 31, 2022 and 2021 is included under the following captions in the unaudited condensed consolidated statements of operations (in thousands):


	Three Months Ended				Nine Months Ended
	March 31,				March 31,
	2022		2021		2022		2021
Research and development	$	327	$	284	$	1,014	$	1,098
General and administrative		523		246		1,687		1,207
Total	$	850	$	530	$	2,701	$	2,305

Unrecognized share-based compensation expense is approximately $6.8 million as of March 31, 2022. This amount is expected to be recognized over a weighted average period of 3.0 years.

Warrants

In connection with the 2021 Underwritten Offering discussed in Note 6, the Company issued 1,661,461 2021 PFWs to purchase 1,661,461 shares of common stock at an issuance price of $6.49 per warrant for gross proceeds of $10.8 million. The 2021 PFWs may be exercised at any time by paying the exercise price of $0.01 per share, subject to the terms discussed in Note 6.

In addition, the Company has issued warrants in conjunction with various debt and equity financings and for services. The following table sets forth a summary of the warrant activity (excluding the 2021 PFWs) for the nine months ended March 31, 2022 (shares in thousands):


	Shares	Price ⁽¹⁾		Term ⁽²⁾
Outstanding, beginning of period	1,252	$	28.91	4.8
Warrant expirations	(94)		95.79
Outstanding, end of period	1,158		23.45	4.4

(1)	Represents the weighted average exercise price.

(2)	Represents the weighted average remaining contractual term for the number of years until the warrants expire.