Stock Based Compensation - Changes in stock options (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Number of Options
Outstanding at Beginning of period (in shares)	3,209,517
Granted (in shares)	0
Exercised (in shares)	(24,434)
Forfeited (in shares)	(37,920)
Expired (in shares)	(1,469)
Outstanding at end of period (in shares)	3,145,694
Vested and exercisable at end of period (in shares)	1,516,647
Weighted Average Exercise Price per Share
Outstanding at Beginning of period (in dollars per share)	$ 1.66
Exercised (in dollars per share)	0.23
Forfeited (in dollars per share)	0.22
Expired (in dollars per share)	0.58
Outstanding at end of period (in dollars per share)	1.69
Vested and exercisable at end of period (in dollars per share)	$ 0.56
Weighted Average Remaining Life
Outstanding at end of period	7 years 1 month 6 days
Vested and exercisable at end of period	5 years 7 months 6 days
Weighted average grant date fair value of stock options granted		$ 3.59
Aggregate Intrinsic Value, Outstanding	$ 13,394
Aggregate Intrinsic Value, Vested and exercisable	7,859
Intrinsic value of stock options exercised	$ 106	$ 517