SHARE-BASED COMPENSATION (Tables)

3 Months Ended

Mar. 31, 2022

Share-based Payment Arrangement [Abstract]

Schedule of Summary of Balances by Plan

As of March 31, 2022, the Company had the following balances by plan:

	Stock Options Outstanding	Shares Available for Issuance
Inducement Awards	720,000	—
2020 Plan	816,886	960,049
2016 Plan	3,264,312	30,289
2008 Plan	513	—
Total	4,801,711	990,338

Schedule of Stock Option Activity

A summary of common stock option activity is as follows:

	Number of Options	Weighted-Average Exercise Price	Weighted-Average Remaining Contractual Term (years)	Aggregate Intrinsic Value (in thousands)
Outstanding as of December 31, 2021	3,683,839	$16.94	8.94	$	15,969
Granted	1,196,000	$18.54	—	—
Exercised	(47,735)	$13.98	—	—
Forfeited or expired	(30,393)	$20.68	—	—
Outstanding as of March 31, 2022	4,801,711	$17.34	9.05	$	13,414
Outstanding as of March 31, 2022 - vested and expected to vest	4,801,711	$17.34	9.05	$	13,414
Exercisable as of March 31, 2022	844,307	$17.00	7.99	$	4,293

Schedule of Fair Value Assumptions for Stock Options

The fair value was determined by the Black-Scholes option pricing model using the following weighted-average assumptions:

	Three Months Ended March 31,
	2022	2021
Expected term, in years	5.81	5.90
Expected volatility	88.0%	126.2%
Risk-free interest rate	1.63%	0.6%
Expected dividend yield	—%	—%
Weighted average exercise price	$18.54	$22.33

Schedule of Allocation of Share-based Compensation Expense

Share-based compensation related to all equity awards issued pursuant to the Equity Incentive Plans, Inducement Plan, and for shares to be issued under the ESPP for the purchase periods active during each respective period is included in the condensed consolidated statements of operations and comprehensive loss as follows:

	Three Months Ended March 31,
	2022		2021
	(in thousands)
Research and development	$	1,545	$	1,111
General and administrative	3,114		2,064
Total share-based compensation expense	$	4,659	$	3,175