Net Loss Per Common Share -Schedules of Net Loss Per Share and Dilutive Securities (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Basic and diluted net loss per common share calculation:
Net loss	$ (26,795)	$ (15,076)
Weighted average common shares outstanding - basic and dilutive (in shares)	93,311	53,426
Net loss per share of common stock -basic and diluted (in dollars per share)	$ (0.29)	$ (0.28)
Anti-dilutive securities
Total (in shares)	11,216	8,036
Stock options outstanding
Anti-dilutive securities
Total (in shares)	9,178	6,635
Restricted stock units
Anti-dilutive securities
Total (in shares)	2,038	1,401