Equity Incentive Plans (Tables)

6 Months Ended

Jun. 30, 2022

Equity Incentive Plans

Summary of stock option activity under the Equity Plans

		Weighted
		Average		Weighted		Aggregate
		Exercise Price		Average Remaining		Intrinsic
	Options	Per Share		Life in Years		Value
Outstanding at December 31, 2021	8,525,618	$	4.48	7.58
Granted	745,000	$	1.89
Forfeited	(224,198)	$	2.10
Outstanding at June 30, 2022	9,046,420	$	4.31	7.20	$	2
Options exercisable at June 30, 2022	6,499,613	$	5.20	6.62	$	1
Options vested and expected to vest at June 30, 2022	9,046,420	$	4.31	7.20	$	2

Schedule of assumptions used to determine grant-date fair value of stock options

	Six Months		Six Months
	Ended June 30,		Ended June 30,
	2022		2021
Expected volatility	82.70	%	66.94	%
Weighted average risk-free interest rate	1.82	%	0.8	%
Expected dividend yield	0.00	%	0.00	%
Expected term (in years)	6.44		6.86

Summary of RSU activity under the 2016 Plan

		Weighted
		Average Grant
	Number of Shares	Date Fair Value
Outstanding at December 31, 2021	935,606	$	1.76
Awarded	2,575,000	$	1.94
Outstanding at June 30, 2022	3,510,606	$	1.89

Schedule of recognized stock-based compensation expense related to the issuance of stock option awards and RSUs to employees and non-employees in the condensed consolidated statements of operations

	Three Months Ended June 30,				Six Months Ended June 30,
	2022		2021		2022		2021
Research and development	$	617	$	398	$	1,171	$	743
General and administrative		649		514		1,299		1,002
Total	$	1,266	$	912	$	2,470	$	1,745