Stock-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2020

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Restricted Stock Activity

The following table summarizes restricted stock activity for the six months ended June 30, 2020:

	Restricted Stock
	Shares			Weighted Average Grant Date Fair Value
Unvested as of January 1, 2020		4,403,148		$	1.87
Granted		64,016			3.19
Forfeited		(6,710	)		3.01
Vested		(702,119	)		1.88
Unvested as of June 30, 2020		3,758,335		$	1.89

Summary of Stock Option Activity

The following table summarizes stock option activity:

	Stock Options
	Shares		Weighted Average Exercise Price		Weighted Average Contractual Life (in years)		Aggregate Intrinsic Value
Options outstanding as of January 1, 2020		44,960	$	3.01		9.5
Granted		53,683		4.50		9.9
Exercised		—		—		—
Forfeited		—		—		—
Options outstanding as of June 30, 2020		98,643	$	3.82		9.6		—
Options vested and exercisable at June 30, 2020		11,238		3.01		9.3		—

Schedule of Estimated Fair Value Assumptions Using Black Scholes Option-Pricing Model

The fair value was estimated on the date of grant using the Black Scholes option-pricing model, with the following assumptions:

	Three Months Ended June 30, 2020
Expected term (in years)		6.11
Expected volatility		89.5	%
Risk-free interest rate		0.48	%
Expected dividend yield		—
Fair value of common stock	$	4.60

Schedule of Stock-based Compensation Expense

Stock-based compensation expense was as follows:

	Three Months Ended June 30,				Six Months Ended June 30,
(in thousands)	2020		2019		2020		2019
Research and development	$	94	$	168	$	308	$	182
General and administrative		398		1,273		830		1,490
Total stock-based compensation expense	$	492	$	1,441	$	1,138	$	1,672