Stock Incentive Plans - Stock option activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Shares
Outstanding, beginning of period (in shares)	227,846
Granted (in shares)	1,156,646
Assumed in Quellis Acquisition (in shares)	55,414
Exercised (in shares)	(10,470)
Cancelled or forfeited (in shares)	(81,196)
Expired (in shares)	(1,507)
Outstanding, end of period (in shares)	1,346,733	227,846
Vested and exercisable (in shares)	135,412
Weighted-Average Exercise Price
Outstanding, beginning of period (in dollars per share)	$ 68.25
Granted (in dollars per share)	15.91
Assumed in Quellis Acquisition (in dollars per share)	1.73
Exercised (in dollars per share)	2.10
Cancelled or forfeited (in dollars per share)	48.13
Expired (in dollars per share)	100.85
Outstanding at end of year (in dollars per share)	22.25	$ 68.25
Vested and Exercisable (in dollars per share)	$ 72.76
Weighted Average Remaining Contractual Term (years)
Outstanding	9 years 7 days	8 years 1 month 17 days
Vested and Exercisable	7 years 2 months 8 days
Aggregate Intrinsic Value
Outstanding	$ 168,181
Vested and Exercisable	77,798
Stock options
Additional disclosures
Intrinsic value of options exercised	$ 45	$ 29
Weighted average grant date fair value of options granted (in dollars per share)	$ 9.82	$ 3.81
Unrecognized compensation expense related to unvested stock option awards	$ 10,800
Weighted-average amortization period over which cost is expected to be recognized	2 years 10 months 24 days