Stock-based Compensation, Stock Options (Details) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2021 USD ($) $ / shares shares	Sep. 30, 2020 shares
Weighted average remaining contractual term [Abstract]
Exercisable	9 months 18 days
Unrecognized compensation expense | $	$ 167
Stock Options [Member]
Number of shares [Abstract]
Outstanding at beginning period (in shares) | shares	5,292,888
Granted (in shares) | shares	2,043,714	0
Exercised (in shares) | shares	(1,557,628)
Forfeited/expired (in shares) | shares	(1,815,085)
Outstanding at end of period (in shares) | shares	3,963,889
Exercisable at end of period (in shares) | shares	1,236,841
Weighted average exercise price per share [Abstract]
Outstanding at beginning of period (in dollars per share)	$ 1.87
Granted (in dollars per share)	1.67
Exercised (in dollars per share)	1.12
Forfeited/expired (in dollars per share)	1.84
Outstanding at end of period (in dollars per share)	2.05
Exercisable at end of period (in dollars per share)	$ 2.77
Weighted average remaining contractual term [Abstract]
Outstanding	8 years 2 months 12 days
Exercisable	5 years 7 months 6 days
Weighted-average grant date fair value (in dollars per share)	$ 1.24
Unrecognized compensation expense | $	$ 2,720
Unrecognized compensation expense, weighted average period	2 years 4 months 24 days
Aggregate intrinsic value of options outstanding | $	$ 558
Aggregate intrinsic value of options exercisable | $	$ 53