Segment Information (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2016 USD ($) segment	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Segment Information
Number of Operating Segments | segment									1
Total revenue	$ 5,692	$ 19,075	$ 5,471	$ 18,410	$ 3,893	$ 10,698	$ 7,134	$ 20,401	$ 48,648	$ 42,126	$ 11,688
Mylan | Total revenue | Customer concentration risk
Segment Information
Percentage of total revenue									31.00%	46.00%
Takeda Pharmaceuticals | Total revenue | Customer concentration risk
Segment Information
Percentage of total revenue									31.00%
Trek Therapeutics | Total revenue | Customer concentration risk
Segment Information
Percentage of total revenue										20.00%
Clinigen | Total revenue | Customer concentration risk
Segment Information
Percentage of total revenue											43.00%
R-Pharm | Total revenue | Customer concentration risk
Segment Information
Percentage of total revenue											19.00%
United States
Segment Information
Total revenue									$ 33,179	$ 16,981	$ 4,231
Europe
Segment Information
Total revenue									15,211	21,354	7,456
Asia
Segment Information
Total revenue									254	2,902
Other
Segment Information
Total revenue									$ 4	$ 889	$ 1