Net Loss per Common Share - Antidilutive securities (Details) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Antidilutive securities
Total antidilutive securities	69,167	6,807	49,430	6,807
Stock options
Antidilutive securities
Total antidilutive securities	4,756	3,844	4,756	3,844
Restricted stock units
Antidilutive securities
Total antidilutive securities	376	194	376	194
Common stock warrants
Antidilutive securities
Total antidilutive securities	8,138	2,769	8,138	2,769
Convertible preferred stock
Antidilutive securities
Total antidilutive securities	2,369		2,369
Future tranche right liability
Antidilutive securities
Total antidilutive securities	53,528		33,791