Common Stock and Stock-Based Awards (Tables)

9 Months Ended

Sep. 30, 2020

Equity [Abstract]

Summary of Stock Option Activity

The following table summarizes the Company’s stock option activity since December 31, 2019:

	Number of Shares			Weighted Average Exercise Price		Weighted Average Remaining Contractual Term		Aggregate Intrinsic Value
						(in years)
Outstanding as of December 31, 2019		8,310,683		$	10.36		7.01	$	3,427
Granted		4,574,365			4.59
Exercised		(1,969,308	)		6.15
Forfeited		(1,113,107	)		10.66
Outstanding as of September 30, 2020		9,802,633		$	8.47		7.93	$	196,033
Options exercisable as of September 30, 2020		3,264,289		$	14.60		5.91	$	46,335

Summary of Restricted Stock Unit Activity

The Company has granted restricted stock units with time-based vesting conditions.  The table below summarizes the Company’s restricted stock unit activity since December 31, 2019:

	Number of Shares			Weighted Average Grant Date Fair Value
Unvested restricted stock units as of December 31, 2019		130,000		$	8.86
Granted		—			—
Forfeited		(5,000	)	$	2.29
Vested		(125,000	)	$	9.12
Unvested restricted stock units as of September 30, 2020		—		$	—

Summary of Stock Based Compensation Expense

The Company recorded stock-based compensation expense in the following expense categories of its condensed consolidated statements of operations and comprehensive loss (in thousands):

	Three Months Ended September 30,				Nine Months Ended September 30,
	2020		2019		2020		2019
Research and development expenses	$	1,368	$	1,033	$	3,358	$	3,574
General and administrative expenses		881		1,004		2,764		2,625
	$	2,249	$	2,037	$	6,122	$	6,199