Equity Incentive Plans (Tables)

3 Months Ended

Mar. 31, 2022

Equity Incentive Plans

Assumptions used in the black-Scholes model

There were no grants of stock options during the three months ended March 31, 2022. The assumptions used in the Black-Scholes model during the three months ended March 31, 2021 are presented below:

	March 31, 2021
Risk-free interest rate	0.93% - 1.29%
Expected volatility	93.37%
Expected term (in years)	5.50 - 7.00
Expected dividend yield	0%

Allocation of Stock-Based Compensation Expenses

The tables below summarize the total stock-based compensation expense included in the Company’s consolidated statements of operations for the periods presented:

	Three Months Ended March 31,
	2022		2021
Research and development	$	303,000	$	353,000
General and administrative		190,000		489,000
Total stock-based compensation	$	493,000	$	842,000

Summary of Stock Option Activity

Stock option transactions during the three months ended March 31, 2022 are presented below:

	Options Outstanding
				Weighted
				Average
		Weighted		Remaining
		Average		Contractual	Aggregate
		Exercise		Term	Intrinsic
	Shares	Price		(Years)	Value
Outstanding at December 31, 2021	2,409,682	$	5.64	8.00		—
Granted	—		—			—
Exercised	—		—			—
Forfeited/Cancelled	(103,343)		9.50			—
Outstanding at March 31, 2022	2,306,339	$	5.47	7.80	$	2,598,000
Vested and expected to vest at March 31, 2022	2,306,339	$	5.47	7.80	$	2,598,000
Exercisable at March 31, 2022	952,421	$	7.70	7.08	$	1,173,000

Schedule of restricted stock awards

Restricted stock awards and restricted stock units during the three months ended March 31, 2022 are presented below:

		Weighted Avg
		Grant Date
	Shares	Fair Value
Outstanding at December 31, 2021	154,018	$	27.49
Granted	—		—
Forfeited/Cancelled	(246)		35.22
Vested and Issued as Common Stock	—		—
Outstanding at March 31, 2022	153,772	$	27.48

Shares Reserved for Future Issuance

As of March 31, 2022, the Company had reserved shares of its common stock for future issuance as follows:

	Shares Reserved
Stock options outstanding	2,306,339
Unvested restricted stock units	30,000
Employee stock purchase plan	9,748
Available for future grants under the 2016 Plan	1,667,037
Warrants outstanding	21,147,219
Total shares reserved	25,160,343