Common Stock and Stock-Based Awards (Tables)

3 Months Ended

Mar. 31, 2020

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		2,957,750			3.30
Exercised		(110,967	)		0.48
Forfeited		(401,873	)		8.62
Outstanding as of March 31, 2020		10,755,593		$	8.58		7.38	$	4,055
Options vested and expected to vest as of March 31, 2020		10,755,593		$	8.58		7.38	$	4,055
Options exercisable as of March 31, 2020		5,080,248		$	12.41		5.38	$	3,110

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		—			—
Vested		(110,000	)		9.98
Unvested restricted stock units as of March 31, 2020		20,000		$	2.69

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:

	Three Months Ended March 31,
	2020		2019
Research and development expenses	$	1,004	$	1,448
General and administrative expenses		955		617
	$	1,959	$	2,065