Significant Accounting Policies - Property and Equipment Useful Lives (Details)	9 Months Ended
	Sep. 30, 2019
Computers and Software
Property Plant And Equipment [Line Items]
Property and Equipment, Useful Lives	3 years
Laboratory Equipment | Minimum
Property Plant And Equipment [Line Items]
Property and Equipment, Useful Lives	3 years
Laboratory Equipment | Maximum
Property Plant And Equipment [Line Items]
Property and Equipment, Useful Lives	6 years 6 months
Furniture | Minimum
Property Plant And Equipment [Line Items]
Property and Equipment, Useful Lives	5 years
Furniture | Maximum
Property Plant And Equipment [Line Items]
Property and Equipment, Useful Lives	16 years 6 months
Manufacturing Equipment
Property Plant And Equipment [Line Items]
Property and Equipment, Useful Lives	2 years