Stock Incentive Plans (Tables)

9 Months Ended

Sep. 30, 2021

Stock Incentive Plans

Summary of stock option activity

				Weighted
				Average
		Weighted-		Remaining	Aggregate
		Average		Contractual	Intrinsic Value
	Shares	Exercise Price		Term (years)	(in thousands)
Outstanding at December 31, 2020	227,846	$	68.25	8.13	$	—
Granted	1,113,982	$	16.21
Assumed in Quellis Acquisition	55,414	$	1.73
Exercised	(2,992)	$	2.10
Cancelled or forfeited	(58,344)	$	62.08
Expired	(1,507)	$	100.85
Outstanding at September 30, 2021	1,334,399	$	22.43	9.25	$	374
Vested and exercisable at September 30, 2021	127,064	$	74.71	7.38	$	178