Net Loss Per Common Share - Narrative (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Numerator:
Net loss	$ (8,269)	$ (4,705)	$ (19,792)	$ (2,844)	$ (12,974)	$ (22,636)
Denominator for basic and diluted EPS:
Basic and diluted EPS: weighted-average common shares outstanding (in shares)	45,137		43,956		45,031	43,841
Net loss per share attributable to common shareholders (Basic and Diluted) (in dollars per share)	$ (0.18)		$ (0.45)		$ (0.29)	$ (0.52)
Service-based stock options
Denominator for basic and diluted EPS:
Aggregate number of common equivalent shares (related to options, warrants and preferred stock) that have been excluded from computations of diluted net loss per common share (in shares)	6,000		5,600		6,000	5,600
Restricted Stock Units (RSUs)
Denominator for basic and diluted EPS:
Aggregate number of common equivalent shares (related to options, warrants and preferred stock) that have been excluded from computations of diluted net loss per common share (in shares)	300		200		300	200
Warrants
Denominator for basic and diluted EPS:
Aggregate number of common equivalent shares (related to options, warrants and preferred stock) that have been excluded from computations of diluted net loss per common share (in shares)	0		100		0	100