Revenues (Narrative) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($)
Transaction price allocated to the remaining performance obligation	$ 1,510
Research and development milestone payments	$ 4,479
Percentages of recognized in next three year	60.00%
Percentages of remaining recognized in next two years	40.00%
Commercial sales milestone payments	$ 28,751