Collaborations and Other Arrangements - ITG (Details) - ITG - Supply agreement - USD ($) $ in Millions	1 Months Ended
	Jul. 31, 2018	Sep. 30, 2018	Aug. 31, 2018
ITG Global Supply Agreement
Number of years in each successive agreement term extension	2 years
Upfront cash payment			$ 5.8
Other current assets
ITG Global Supply Agreement
Upfront cash payment		$ 5.3
Other noncurrent assets
ITG Global Supply Agreement
Upfront cash payment		$ 0.5
Product required for phase 3 VISION trial
ITG Global Supply Agreement
Amount of product to be purchased as a percentage of requirements	100.00%
Product volume needs during commercial phase | Minimum
ITG Global Supply Agreement
Amount of product to be purchased as a percentage of requirements	50.00%
Product volume needs during commercial phase | Maximum
ITG Global Supply Agreement
Amount of product to be purchased as a percentage of requirements	100.00%