Stock-based Compensation (Tables)

6 Months Ended

Jun. 30, 2022

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Summary of Stock Option Activity with in 2014 Stock Incentive Plan and 2019 Incentive Award Plan

The below summary includes stock option activity within the Company’s 2014 Stock Incentive Plan and 2019 Incentive Award Plan for the six months ended June 30, 2022:

	Number of shares			Weighted average exercise		Weighted average remaining contractual term		Aggregate intrinsic
	in Plans			price		(in years)		value
Outstanding as of December 31, 2021		6,830,037		$	14.72		7.76	$	6,987
Granted		172,176			2.19		8.91		—
Exercised		(9,997	)		1.24		—	$	37
Forfeited		(924,065	)		19.72		—		—
Outstanding as of June 30, 2022		6,068,151		$	13.63		6.86	$	789
Options exercisable as of June 30, 2022		4,390,918		$	10.59		6.39	$	759
Options unvested as of June 30, 2022		1,677,233		$	21.58		8.07	$	30

Summary of Grant-date Fair Value of Stock Options Granted on Weighted Average Basis

The assumptions that the Company used to determine the grant-date fair value of stock options granted to employees and directors were as follows, presented on a weighted average basis:

	June 30,
	2022
Risk-free interest rate		2.9	%
Expected term (in years)		6.0
Expected volatility		80.0	%
Expected dividend yield		0.0	%

Summary of Status of Restricted Common Stock and Restricted Stock Units

The below summary includes restricted stock unit activity within the Company's 2019 Incentive Award Plan for the six months ended June 30, 2022:

	Number of shares			Weighted average fair value
Unvested, December 31, 2021		626,300		$	9.54
Awarded		2,426,650			3.77
Vested		(310,600	)		9.54
Forfeited		(436,850	)		5.40
Unvested as of June 30, 2022		2,305,500		$	4.25

Summary of Recognized Stock-based Compensation

The Company recognized stock-based compensation within the accompanying consolidated statements of operations as follows:

	Three Months Ended June 30,				Six Months Ended June 30,
	2022		2021		2022		2021
Research and development	$	1,598	$	3,090	$	3,899	$	4,619
General and administrative		2,966		2,999		5,931		6,081
Total	$	4,564	$	6,089	$	9,830	$	10,700