Share-Based Payment Awards (Tables)

9 Months Ended

Sep. 30, 2023

Share-Based Payment Arrangement [Abstract]

Stock Option Activity Under Plan

The following table provides a reconciliation of stock option activity under the Company’s equity incentive plan and for inducement awards for the nine months ended September 30, 2023:

	Number of Options			Weighted Average Exercise Price		Weighted Average Remaining Contractual Life		Aggregate Intrinsic Value
						(in years)		(in thousands)
Outstanding at January 1, 2023		4,082,555		$	13.79
Granted		2,739,861			4.28
Exercised		(56,090	)		11.31
Forfeited		(373,911	)		7.01
Expired		(51,753	)		25.98
Outstanding at September 30, 2023		6,340,662		$	10.00		8.07	$	10,437
Exercisable at September 30, 2023		2,354,229		$	15.69		6.54	$	42

Schedule of Key Assumptions Used

In determining the grant date fair value of option awards during the nine months ended September 30, 2023, the Company applied the Black-Scholes option pricing model based on the following key assumptions:

Option life (in years)	5.27 - 6.08
Stock volatility	78% - 88%
Risk-free interest rate	3.44% - 4.38%
Expected dividends	0.0%

Summary of Information about Stock Options

The following table summarizes information about employee, non-executive director and external consultant stock options for the nine months ended September 30, 2023 (in thousands except per share amount):

	Nine Months
	Ended
	September 30, 2023
Weighted average grant date fair value per share	$	3.07
Total cash received from exercise of stock options		634
Total intrinsic value of stock options exercised		138

Summary of Restricted Stock Unit Activity

The following table provides a reconciliation of RSU activity under the 2016 Plan and the 2023 Plan for the nine months ended September 30, 2023:

	Number of Restricted Stock Units			Weighted Average Grant Date Fair Value
Nonvested at January 1, 2023		509,170		$	10.81
Granted		1,071,354			3.92
Vested		(201,414	)		11.04
Forfeited		(45,368	)		8.63
Nonvested at September 30, 2023		1,333,742		$	5.31

Compensation Expense from Stock-Based Payment Awards

The Company’s condensed consolidated statements of comprehensive loss included total compensation expense from stock-based payment awards as follows (in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2023		2022		2023		2022
Compensation expense included in:
Research and development	$	1,263	$	1,277	$	3,405	$	4,762
Sales and marketing		60		290		290		1,195
General and administrative		2,306		1,632		4,772		4,859
	$	3,629	$	3,199	$	8,467	$	10,816