Stock-based Compensation (Tables)

12 Months Ended

Dec. 31, 2020

Stock-based Compensation

Assumptions used in the black-Scholes model

	Year Ended
	December 31, 2020
Risk-free interest rate	0.13% --1.48%
Expected volatility	90.43% -- 94.0%
Expected term (in years)	5.5 – 7.0
Expected dividend yield	0%

Allocation of Stock-Based Compensation Expenses

	Year Ended December 31,
	2020		2019
Research and development	$	1,252,000	$	872,000
General and administrative		2,223,000		3,398,000
Total stock-based compensation	$	3,475,000	$	4,270,000

	Year Ended
	December 31,
	2020		2019
Expense related to RSA's issued prior to Merger and vesting beginning on Merger closing date	$	2,081,000	$	2,152,000
Acceleration of RSA expense in connection with executive severance		55,000		1,244,000
Expense related to inducement award		166,000		—
Expense related to vesting of stock options issued under the Company's stock plans		1,173,000		874,000
Total stock-based compensation expense	$	3,475,000	$	4,270,000

Summary of Stock Option Activity

	Options Outstanding
				Weighted
				Average
		Weighted		Remaining
		Average		Contractual	Aggregate
		Exercise		Term	Intrinsic
	Shares	Price		(Years)	Value
Outstanding at December 31, 2019	1,275,380	$	7.61	8.81		—
Granted	551,766		3.38	—		—
Exercised	(27,382)		3.15	—		14,000
Forfeited/Cancelled	(130,838)		5.69	—		—
Outstanding at December 31, 2020	1,668,926	$	6.30	8.32	$	—
Vested and expected to vest at December 31, 2020	1,668,926	$	6.30	8.32	$	—
Exercisable at December 31, 2020	439,526	$	14.82	6.75	$	—

Schedule of restricted stock awards

		Weighted Avg
		Grant Date
	Shares	Fair Value
Outstanding at December 31, 2019	343,493	$	21.83
Granted	103,000		3.34
Forfeited/Cancelled	(4,010)		16.02
Vested and Issued as Common Stock	(119,727)		12.24
Outstanding at December 31, 2020	322,756	$	19.55

Shares Reserved for Future Issuance

	Shares Reserved
Stock options outstanding	1,668,926
Unvested restricted stock units	70,000
Employee stock purchase plan	7,605
Available for future grants under the 2016 Plan	138,814
Warrants outstanding	10,547,618
Total shares reserved	12,432,963