Net Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020
Numerator:
Net loss	$ (14,555)	$ (12,367)	$ (14,672)	$ (16,551)	$ (2,334)	$ (16,530)	$ (41,594)	$ (35,415)
Denominator:
Weighted-average number of common shares - basic (in shares)	39,224,863			33,619,379			37,297,892	33,592,846
Loss per common share - basic (in dollars per share)	$ (0.37)			$ (0.49)			$ (1.12)	$ (1.05)
Loss per common share - diluted (in dollars per share)	$ (0.37)			$ (0.49)			$ (1.12)	$ (1.05)
Options on Common Shares Outstanding
Denominator:
Total potentially antidilutive derivatives excluded from losses per share (in shares)							4,341,967	3,167,192
Restricted Stock Units Unvested
Denominator:
Total potentially antidilutive derivatives excluded from losses per share (in shares)							0	14,233
Warrants on Common Shares Outstanding
Denominator:
Total potentially antidilutive derivatives excluded from losses per share (in shares)							1,571,429	1,571,429